diff --git a/leenkx/Sources/iron/App.hx b/leenkx/Sources/iron/App.hx
index 6d0f6f6..676932c 100644
--- a/leenkx/Sources/iron/App.hx
+++ b/leenkx/Sources/iron/App.hx
@@ -12,6 +12,7 @@ class App {
 	static var traitInits: Array<Void->Void> = [];
 	static var traitUpdates: Array<Void->Void> = [];
 	static var traitLateUpdates: Array<Void->Void> = [];
+	static var traitFixedUpdates: Array<Void->Void> = [];
 	static var traitRenders: Array<kha.graphics4.Graphics->Void> = [];
 	static var traitRenders2D: Array<kha.graphics2.Graphics->Void> = [];
 	public static var framebuffer: kha.Framebuffer;
@@ -23,6 +24,8 @@ class App {
 	public static var renderPathTime: Float;
 	public static var endFrameCallbacks: Array<Void->Void> = [];
 	#end
+	static var last = 0.0;
+	static var time = 0.0;
 	static var lastw = -1;
 	static var lasth = -1;
 	public static var onResize: Void->Void = null;
@@ -34,13 +37,14 @@ class App {
 	function new(done: Void->Void) {
 		done();
 		kha.System.notifyOnFrames(render);
-		kha.Scheduler.addTimeTask(update, 0, iron.system.Time.delta);
+		kha.Scheduler.addTimeTask(update, 0, iron.system.Time.step);
 	}
 
 	public static function reset() {
 		traitInits = [];
 		traitUpdates = [];
 		traitLateUpdates = [];
+		traitFixedUpdates = [];
 		traitRenders = [];
 		traitRenders2D = [];
 		if (onResets != null) for (f in onResets) f();
@@ -49,6 +53,8 @@ class App {
 	static function update() {
 		if (Scene.active == null || !Scene.active.ready) return;
 		if (pauseUpdates) return;
+		
+		iron.system.Time.update();
 
 		#if lnx_debug
 		startTime = kha.Scheduler.realTime();
@@ -56,6 +62,14 @@ class App {
 
 		Scene.active.updateFrame();
 
+
+		time += iron.system.Time.delta;
+
+		while (time >= iron.system.Time.fixedStep) {
+			for (f in traitFixedUpdates) f();
+			time -= iron.system.Time.fixedStep;
+		}
+
 		var i = 0;
 		var l = traitUpdates.length;
 		while (i < l) {
@@ -106,7 +120,7 @@ class App {
 		var frame = frames[0];
 		framebuffer = frame;
 
-		iron.system.Time.update();
+		iron.system.Time.render();
 
 		if (Scene.active == null || !Scene.active.ready) {
 			render2D(frame);
@@ -172,6 +186,14 @@ class App {
 		traitLateUpdates.remove(f);
 	}
 
+	public static function notifyOnFixedUpdate(f: Void->Void) {
+		traitFixedUpdates.push(f);
+	}
+
+	public static function removeFixedUpdate(f: Void->Void) {
+		traitFixedUpdates.remove(f);
+	}
+
 	public static function notifyOnRender(f: kha.graphics4.Graphics->Void) {
 		traitRenders.push(f);
 	}
diff --git a/leenkx/Sources/iron/Trait.hx b/leenkx/Sources/iron/Trait.hx
index 854385d..dd63b00 100644
--- a/leenkx/Sources/iron/Trait.hx
+++ b/leenkx/Sources/iron/Trait.hx
@@ -16,6 +16,7 @@ class Trait {
 	var _remove: Array<Void->Void> = null;
 	var _update: Array<Void->Void> = null;
 	var _lateUpdate: Array<Void->Void> = null;
+	var _fixedUpdate: Array<Void->Void> = null;
 	var _render: Array<kha.graphics4.Graphics->Void> = null;
 	var _render2D: Array<kha.graphics2.Graphics->Void> = null;
 
@@ -87,6 +88,23 @@ class Trait {
 		App.removeLateUpdate(f);
 	}
 
+    /**
+      Add fixed game logic handler.
+    **/
+	public function notifyOnFixedUpdate(f: Void->Void) {
+		if (_fixedUpdate == null) _fixedUpdate = [];
+		_fixedUpdate.push(f);
+		App.notifyOnFixedUpdate(f);
+	}
+
+    /**
+      Remove fixed game logic handler.
+    **/
+	public function removeFixedUpdate(f: Void->Void) {
+		_fixedUpdate.remove(f);
+		App.removeFixedUpdate(f);
+	}
+
     /**
       Add render handler.
     **/
diff --git a/leenkx/Sources/iron/data/SceneFormat.hx b/leenkx/Sources/iron/data/SceneFormat.hx
index ff88e8e..a499d3f 100644
--- a/leenkx/Sources/iron/data/SceneFormat.hx
+++ b/leenkx/Sources/iron/data/SceneFormat.hx
@@ -392,6 +392,8 @@ typedef TParticleData = {
 #end
 	public var name: String;
 	public var type: Int; // 0 - Emitter, Hair
+	public var auto_start: Bool;
+	public var is_unique: Bool;
 	public var loop: Bool;
 	public var count: Int;
 	public var frame_start: FastFloat;
diff --git a/leenkx/Sources/iron/object/Animation.hx b/leenkx/Sources/iron/object/Animation.hx
index e86f500..1a3ec9b 100644
--- a/leenkx/Sources/iron/object/Animation.hx
+++ b/leenkx/Sources/iron/object/Animation.hx
@@ -159,9 +159,17 @@ class Animation {
 			if(markerEvents.get(sampler) != null){
 				for (i in 0...anim.marker_frames.length) {
 					if (frameIndex == anim.marker_frames[i]) {
-						var marketAct = markerEvents.get(sampler);
-						var ar = marketAct.get(anim.marker_names[i]);
+						var markerAct = markerEvents.get(sampler);
+						var ar = markerAct.get(anim.marker_names[i]);
 						if (ar != null) for (f in ar) f();
+					} else {
+						for (j in 0...(frameIndex - lastFrameIndex)) {
+							if (lastFrameIndex + j + 1 == anim.marker_frames[i]) {
+								var markerAct = markerEvents.get(sampler);
+								var ar = markerAct.get(anim.marker_names[i]);
+								if (ar != null) for (f in ar) f();
+							}
+						}
 					}
 				}
 				lastFrameIndex = frameIndex;
diff --git a/leenkx/Sources/iron/object/Object.hx b/leenkx/Sources/iron/object/Object.hx
index 8a68e82..4c4987b 100644
--- a/leenkx/Sources/iron/object/Object.hx
+++ b/leenkx/Sources/iron/object/Object.hx
@@ -172,6 +172,10 @@ class Object {
 			for (f in t._init) App.removeInit(f);
 			t._init = null;
 		}
+		if (t._fixedUpdate != null) {
+			for (f in t._fixedUpdate) App.removeFixedUpdate(f);
+			t._fixedUpdate = null;
+		}
 		if (t._update != null) {
 			for (f in t._update) App.removeUpdate(f);
 			t._update = null;
diff --git a/leenkx/Sources/iron/object/ParticleSystem.hx b/leenkx/Sources/iron/object/ParticleSystem.hx
index 5c94f08..baeabac 100644
--- a/leenkx/Sources/iron/object/ParticleSystem.hx
+++ b/leenkx/Sources/iron/object/ParticleSystem.hx
@@ -2,6 +2,7 @@ package iron.object;
 
 #if lnx_particles
 
+import kha.FastFloat;
 import kha.graphics4.Usage;
 import kha.arrays.Float32Array;
 import iron.data.Data;
@@ -16,39 +17,45 @@ import iron.math.Vec4;
 class ParticleSystem {
 	public var data: ParticleData;
 	public var speed = 1.0;
+	var currentSpeed = 0.0;
 	var particles: Array<Particle>;
 	var ready: Bool;
-	public var frameRate = 24;
-	public var lifetime = 0.0;
-	public var animtime = 0.0;
-	public var time = 0.0;
-	public var spawnRate = 0.0;
+	var frameRate = 24;
+	var lifetime = 0.0;
+	var animtime = 0.0;
+	var time = 0.0;
+	var spawnRate = 0.0;
+	var looptime = 0.0;
 	var seed = 0;
 
-	public var r: TParticleData;
-	public var gx: Float;
-	public var gy: Float;
-	public var gz: Float;
-	public var alignx: Float;
-	public var aligny: Float;
-	public var alignz: Float;
+	var r: TParticleData;
+	var gx: Float;
+	var gy: Float;
+	var gz: Float;
+	var alignx: Float;
+	var aligny: Float;
+	var alignz: Float;
 	var dimx: Float;
 	var dimy: Float;
 	var tilesx: Int;
 	var tilesy: Int;
 	var tilesFramerate: Int;
 
-	public var count = 0;
-	public var lap = 0;
-	public var lapTime = 0.0;
+	var count = 0;
+	var lap = 0;
+	var lapTime = 0.0;
 	var m = Mat4.identity();
 
 	var ownerLoc = new Vec4();
 	var ownerRot = new Quat();
 	var ownerScl = new Vec4();
+	
+	var random = 0.0;
 
 	public function new(sceneName: String, pref: TParticleReference) {
 		seed = pref.seed;
+		currentSpeed = speed;
+		speed = 0;
 		particles = [];
 		ready = false;
 		
@@ -65,34 +72,61 @@ class ParticleSystem {
 				gy = 0;
 				gz = -9.81 * r.weight_gravity;
 			}
-			alignx = r.object_align_factor[0] / 2;
-			aligny = r.object_align_factor[1] / 2;
-			alignz = r.object_align_factor[2] / 2;
+			alignx = r.object_align_factor[0];
+			aligny = r.object_align_factor[1];
+			alignz = r.object_align_factor[2];
+			looptime = (r.frame_end - r.frame_start) / frameRate;
 			lifetime = r.lifetime / frameRate;
-			animtime = (r.frame_end - r.frame_start) / frameRate;
+			animtime = r.loop ? looptime : looptime + lifetime;
 			spawnRate = ((r.frame_end - r.frame_start) / r.count) / frameRate;
 
 			for (i in 0...r.count) {
-				var particle = new Particle(i);
-				particle.sr = 1 - Math.random() * r.size_random;
-				particles.push(particle);
+				particles.push(new Particle(i));
 			}
 
 			ready = true;
+			if (r.auto_start){
+				start();
+			}
 		});
 	}
 
+	public function start() {
+		if (r.is_unique) random = Math.random();
+		lifetime = r.lifetime / frameRate;
+		time = 0;
+		lap = 0;
+		lapTime = 0;
+		speed = currentSpeed;
+	}
+
 	public function pause() {
-		lifetime = 0;
+		speed = 0;
 	}
 
 	public function resume() {
 		lifetime = r.lifetime / frameRate;
+		speed = currentSpeed;
 	}
 
+
+
+	// TODO: interrupt smoothly
+	public function stop() {
+		end();
+	}
+
+	function end() {
+		lifetime = 0;
+		speed = 0;
+		lap = 0;
+	}
+	
 	public function update(object: MeshObject, owner: MeshObject) {
 		if (!ready || object == null || speed == 0.0) return;
 
+		var prevLap = lap;
+
 		// Copy owner world transform but discard scale
 		owner.transform.world.decompose(ownerLoc, ownerRot, ownerScl);
 		object.transform.loc = ownerLoc;
@@ -115,17 +149,21 @@ class ParticleSystem {
 		}
 
 		// Animate
-		time += Time.delta * speed;
+		time += Time.renderDelta * speed; // realDelta to renderDelta
 		lap = Std.int(time / animtime);
 		lapTime = time - lap * animtime;
 		count = Std.int(lapTime / spawnRate);
 
+		if (lap > prevLap && !r.loop) {
+			end();
+		}
+		
 		updateGpu(object, owner);
 	}
 
 	public function getData(): Mat4 {
 		var hair = r.type == 1;
-		m._00 = r.loop ? animtime : -animtime;
+		m._00 = animtime;
 		m._01 = hair ? 1 / particles.length : spawnRate;
 		m._02 = hair ? 1 : lifetime;
 		m._03 = particles.length;
@@ -133,9 +171,9 @@ class ParticleSystem {
 		m._11 = hair ? 0 : aligny;
 		m._12 = hair ? 0 : alignz;
 		m._13 = hair ? 0 : r.factor_random;
-		m._20 = hair ? 0 : gx * r.mass;
-		m._21 = hair ? 0 : gy * r.mass;
-		m._22 = hair ? 0 : gz * r.mass;
+		m._20 = hair ? 0 : gx;
+		m._21 = hair ? 0 : gy;
+		m._22 = hair ? 0 : gz;
 		m._23 = hair ? 0 : r.lifetime_random;
 		m._30 = tilesx;
 		m._31 = tilesy;
@@ -144,13 +182,25 @@ class ParticleSystem {
 		return m;
 	}
 
+	public function getSizeRandom(): FastFloat {
+		return r.size_random;
+	}
+
+	public function getRandom(): FastFloat {
+		return random;
+	}
+
+	public function getSize(): FastFloat {
+		return r.particle_size;
+	}
+
 	function updateGpu(object: MeshObject, owner: MeshObject) {
 		if (!object.data.geom.instanced) setupGeomGpu(object, owner);
 		// GPU particles transform is attached to owner object
 	}
 
-	public function setupGeomGpu(object: MeshObject, owner: MeshObject) {
-		var instancedData = new Float32Array(particles.length * 6);
+	function setupGeomGpu(object: MeshObject, owner: MeshObject) {
+		var instancedData = new Float32Array(particles.length * 3);
 		var i = 0;
 
 		var normFactor = 1 / 32767; // pa.values are not normalized
@@ -169,10 +219,6 @@ class ParticleSystem {
 					instancedData.set(i, pa.values[j * pa.size    ] * normFactor * scaleFactor.x); i++;
 					instancedData.set(i, pa.values[j * pa.size + 1] * normFactor * scaleFactor.y); i++;
 					instancedData.set(i, pa.values[j * pa.size + 2] * normFactor * scaleFactor.z); i++;
-
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
 				}
 
 			case 1: // Face
@@ -196,10 +242,6 @@ class ParticleSystem {
 					instancedData.set(i, pos.x * normFactor * scaleFactor.x); i++;
 					instancedData.set(i, pos.y * normFactor * scaleFactor.y); i++;
 					instancedData.set(i, pos.z * normFactor * scaleFactor.z); i++;
-
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
 				}
 
 			case 2: // Volume
@@ -210,13 +252,9 @@ class ParticleSystem {
 					instancedData.set(i, (Math.random() * 2.0 - 1.0) * scaleFactorVolume.x); i++;
 					instancedData.set(i, (Math.random() * 2.0 - 1.0) * scaleFactorVolume.y); i++;
 					instancedData.set(i, (Math.random() * 2.0 - 1.0) * scaleFactorVolume.z); i++;
-
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
-					instancedData.set(i, p.sr); i++;
 				}
 		}
-		object.data.geom.setupInstanced(instancedData, 3, Usage.StaticUsage);
+		object.data.geom.setupInstanced(instancedData, 1, Usage.StaticUsage);
 	}
 
 	function fhash(n: Int): Float {
@@ -255,10 +293,11 @@ class ParticleSystem {
 
 class Particle {
 	public var i: Int;
-	public var px = 0.0;
-	public var py = 0.0;
-	public var pz = 0.0;
-	public var sr = 1.0; // Size random
+	
+	public var x = 0.0;
+	public var y = 0.0;
+	public var z = 0.0;
+
 	public var cameraDistance: Float;
 
 	public function new(i: Int) {
diff --git a/leenkx/Sources/iron/object/Tilesheet.hx b/leenkx/Sources/iron/object/Tilesheet.hx
index ea4e020..86328e0 100644
--- a/leenkx/Sources/iron/object/Tilesheet.hx
+++ b/leenkx/Sources/iron/object/Tilesheet.hx
@@ -80,7 +80,7 @@ class Tilesheet {
 	function update() {
 		if (!ready || paused || action.start >= action.end) return;
 
-		time += Time.realDelta;
+		time += Time.renderDelta;
 
 		var frameTime = 1 / raw.framerate;
 		var framesToAdvance = 0;
diff --git a/leenkx/Sources/iron/object/Uniforms.hx b/leenkx/Sources/iron/object/Uniforms.hx
index 022a777..473958d 100644
--- a/leenkx/Sources/iron/object/Uniforms.hx
+++ b/leenkx/Sources/iron/object/Uniforms.hx
@@ -1109,6 +1109,26 @@ class Uniforms {
 				case "_texUnpack": {
 					f = texUnpack != null ? texUnpack : 1.0;
 				}
+				#if lnx_particles
+				case "_particleSizeRandom": {
+					var mo = cast(object, MeshObject);
+					if (mo.particleOwner != null && mo.particleOwner.particleSystems != null) {
+						f = mo.particleOwner.particleSystems[mo.particleIndex].getSizeRandom();
+					}
+				}
+				case "_particleRandom": {
+					var mo = cast(object, MeshObject);
+					if (mo.particleOwner != null && mo.particleOwner.particleSystems != null) {
+						f = mo.particleOwner.particleSystems[mo.particleIndex].getRandom();
+					}
+				}
+				case "_particleSize": {
+					var mo = cast(object, MeshObject);
+					if (mo.particleOwner != null && mo.particleOwner.particleSystems != null) {
+						f = mo.particleOwner.particleSystems[mo.particleIndex].getSize();
+					}
+				}
+				#end
 			}
 
 			if (f == null && externalFloatLinks != null) {
diff --git a/leenkx/Sources/iron/system/Time.hx b/leenkx/Sources/iron/system/Time.hx
index c82d802..99484eb 100644
--- a/leenkx/Sources/iron/system/Time.hx
+++ b/leenkx/Sources/iron/system/Time.hx
@@ -7,16 +7,24 @@ class Time {
 		if (frequency == null) initFrequency();
 		return 1 / frequency;
 	}
+	
+	static var _fixedStep: Null<Float>;
+	public static var fixedStep(get, never): Float;
+	static function get_fixedStep(): Float {
+		return _fixedStep;
+	}
+	
 
-	public static var scale = 1.0;
-	public static var delta(get, never): Float;
-	static function get_delta(): Float {
-		if (frequency == null) initFrequency();
-		return (1 / frequency) * scale;
+	public static function initFixedStep(value: Float = 1 / 60) {
+		_fixedStep = value;
 	}
 
-	static var last = 0.0;
-	public static var realDelta = 0.0;
+
+	static var lastTime = 0.0;
+	public static var delta = 0.0;
+
+	static var lastRenderTime = 0.0;
+	public static var renderDelta = 0.0;
 	public static inline function time(): Float {
 		return kha.Scheduler.time();
 	}
@@ -31,7 +39,12 @@ class Time {
 	}
 
 	public static function update() {
-		realDelta = realTime() - last;
-		last = realTime();
+		delta = (realTime() - lastTime) * scale;
+		lastTime = realTime();
+	}
+
+	public static function render() {
+		renderDelta = (realTime() - lastRenderTime) * scale;
+		lastRenderTime = realTime();
 	}
 }
diff --git a/leenkx/Sources/leenkx/logicnode/AddParticleToObjectNode.hx b/leenkx/Sources/leenkx/logicnode/AddParticleToObjectNode.hx
index ae2ff19..5bcd6b0 100644
--- a/leenkx/Sources/leenkx/logicnode/AddParticleToObjectNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/AddParticleToObjectNode.hx
@@ -1,99 +1,99 @@
-package leenkx.logicnode;
-
-import iron.data.SceneFormat.TSceneFormat;
-import iron.data.Data;
-import iron.object.Object;
-
-class AddParticleToObjectNode extends LogicNode {
-
-	public var property0: String;
-
-	public function new(tree: LogicTree) {
-		super(tree);
-	}
-
-	override function run(from: Int) {
-		#if lnx_particles
-
-		if (property0 == 'Scene Active'){		
-			var objFrom: Object = inputs[1].get();
-			var slot: Int = inputs[2].get();
-			var objTo: Object = inputs[3].get();
-	
-			if (objFrom == null || objTo == null) return;
-	
-			var mobjFrom = cast(objFrom, iron.object.MeshObject);
-	
-			var psys = mobjFrom.particleSystems != null ? mobjFrom.particleSystems[slot] : 
-				mobjFrom.particleOwner != null && mobjFrom.particleOwner.particleSystems != null ? mobjFrom.particleOwner.particleSystems[slot] : null;
-
-			if (psys == null) return;
-	
-			var mobjTo = cast(objTo, iron.object.MeshObject);
-	
-			mobjTo.setupParticleSystem(iron.Scene.active.raw.name, {name: 'LnxPS', seed: 0, particle: psys.r.name});
-			
-			mobjTo.render_emitter = inputs[4].get();
-
-			iron.Scene.active.spawnObject(psys.data.raw.instance_object, null, function(o: Object) {
-				if (o != null) {
-					var c: iron.object.MeshObject = cast o;
-					if (mobjTo.particleChildren == null) mobjTo.particleChildren = [];
-					mobjTo.particleChildren.push(c);
-					c.particleOwner = mobjTo;
-					c.particleIndex = mobjTo.particleChildren.length - 1;
-				}
-			});
-	
-			var oslot: Int = mobjTo.particleSystems.length-1;
-			var opsys = mobjTo.particleSystems[oslot];
-			opsys.setupGeomGpu(mobjTo.particleChildren[oslot], mobjTo);
-		
-		} else {
-			var sceneName: String = inputs[1].get();
-			var objectName: String = inputs[2].get();
-			var slot: Int = inputs[3].get();
-
-			var mobjTo: Object = inputs[4].get();
-			var mobjTo = cast(mobjTo, iron.object.MeshObject);
-
-			#if lnx_json
-				sceneName += ".json";
-			#elseif lnx_compress
-				sceneName += ".lz4";
-			#end
-
-			Data.getSceneRaw(sceneName, (rawScene: TSceneFormat) -> {
-
-			for (obj in rawScene.objects) {
-				if (obj.name == objectName) {
-					mobjTo.setupParticleSystem(sceneName, obj.particle_refs[slot]);
-					mobjTo.render_emitter = inputs[5].get();					
-
-					iron.Scene.active.spawnObject(rawScene.particle_datas[slot].instance_object, null, function(o: Object) {
-						if (o != null) {
-							var c: iron.object.MeshObject = cast o;
-							if (mobjTo.particleChildren == null) mobjTo.particleChildren = [];
-							mobjTo.particleChildren.push(c);
-							c.particleOwner = mobjTo;
-							c.particleIndex = mobjTo.particleChildren.length - 1;
-						}
-					}, true, rawScene);
-
-					var oslot: Int = mobjTo.particleSystems.length-1;
-					var opsys = mobjTo.particleSystems[oslot];
-					opsys.setupGeomGpu(mobjTo.particleChildren[oslot], mobjTo);
-
-					break;
-				}
-			}
-
-			});
-
-		}
-
-		#end
-
-		runOutput(0);
-	}
-}
+package leenkx.logicnode;
+
+import iron.data.SceneFormat.TSceneFormat;
+import iron.data.Data;
+import iron.object.Object;
+
+class AddParticleToObjectNode extends LogicNode {
+
+	public var property0: String;
+
+	public function new(tree: LogicTree) {
+		super(tree);
+	}
+
+	override function run(from: Int) {
+		#if lnx_particles
+
+		if (property0 == 'Scene Active'){		
+			var objFrom: Object = inputs[1].get();
+			var slot: Int = inputs[2].get();
+			var objTo: Object = inputs[3].get();
+	
+			if (objFrom == null || objTo == null) return;
+	
+			var mobjFrom = cast(objFrom, iron.object.MeshObject);
+	
+			var psys = mobjFrom.particleSystems != null ? mobjFrom.particleSystems[slot] : 
+				mobjFrom.particleOwner != null && mobjFrom.particleOwner.particleSystems != null ? mobjFrom.particleOwner.particleSystems[slot] : null;
+
+			if (psys == null) return;
+	
+			var mobjTo = cast(objTo, iron.object.MeshObject);
+	
+			mobjTo.setupParticleSystem(iron.Scene.active.raw.name, {name: 'LnxPS', seed: 0, particle: @:privateAccess psys.r.name});
+			
+			mobjTo.render_emitter = inputs[4].get();
+
+			iron.Scene.active.spawnObject(psys.data.raw.instance_object, null, function(o: Object) {
+				if (o != null) {
+					var c: iron.object.MeshObject = cast o;
+					if (mobjTo.particleChildren == null) mobjTo.particleChildren = [];
+					mobjTo.particleChildren.push(c);
+					c.particleOwner = mobjTo;
+					c.particleIndex = mobjTo.particleChildren.length - 1;
+				}
+			});
+	
+			var oslot: Int = mobjTo.particleSystems.length-1;
+			var opsys = mobjTo.particleSystems[oslot];
+			@:privateAccess opsys.setupGeomGpu(mobjTo.particleChildren[oslot], mobjTo);
+		
+		} else {
+			var sceneName: String = inputs[1].get();
+			var objectName: String = inputs[2].get();
+			var slot: Int = inputs[3].get();
+
+			var mobjTo: Object = inputs[4].get();
+			var mobjTo = cast(mobjTo, iron.object.MeshObject);
+
+			#if lnx_json
+				sceneName += ".json";
+			#elseif lnx_compress
+				sceneName += ".lz4";
+			#end
+
+			Data.getSceneRaw(sceneName, (rawScene: TSceneFormat) -> {
+
+			for (obj in rawScene.objects) {
+				if (obj.name == objectName) {
+					mobjTo.setupParticleSystem(sceneName, obj.particle_refs[slot]);
+					mobjTo.render_emitter = inputs[5].get();					
+
+					iron.Scene.active.spawnObject(rawScene.particle_datas[slot].instance_object, null, function(o: Object) {
+						if (o != null) {
+							var c: iron.object.MeshObject = cast o;
+							if (mobjTo.particleChildren == null) mobjTo.particleChildren = [];
+							mobjTo.particleChildren.push(c);
+							c.particleOwner = mobjTo;
+							c.particleIndex = mobjTo.particleChildren.length - 1;
+						}
+					}, true, rawScene);
+
+					var oslot: Int = mobjTo.particleSystems.length-1;
+					var opsys = mobjTo.particleSystems[oslot];
+					@:privateAccess opsys.setupGeomGpu(mobjTo.particleChildren[oslot], mobjTo);
+
+					break;
+				}
+			}
+
+			});
+
+		}
+
+		#end
+
+		runOutput(0);
+	}
+}
diff --git a/leenkx/Sources/leenkx/logicnode/GetFPSNode.hx b/leenkx/Sources/leenkx/logicnode/GetFPSNode.hx
index 0f58c04..f915b7e 100644
--- a/leenkx/Sources/leenkx/logicnode/GetFPSNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/GetFPSNode.hx
@@ -8,7 +8,7 @@ class GetFPSNode extends LogicNode {
 
     override function get(from: Int): Dynamic {
         if (from == 0) {
-            var fps = Math.round(1 / iron.system.Time.realDelta);
+            var fps = Math.round(1 / iron.system.Time.renderDelta);
             if ((fps == Math.POSITIVE_INFINITY) || (fps == Math.NEGATIVE_INFINITY) || (Math.isNaN(fps))) {
                 return 0;
             }
diff --git a/leenkx/Sources/leenkx/logicnode/GetParticleDataNode.hx b/leenkx/Sources/leenkx/logicnode/GetParticleDataNode.hx
index 2b2b669..bad5504 100644
--- a/leenkx/Sources/leenkx/logicnode/GetParticleDataNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/GetParticleDataNode.hx
@@ -1,66 +1,66 @@
-package leenkx.logicnode;
-
-import iron.object.Object;
-
-class GetParticleDataNode extends LogicNode {
-
-	public function new(tree: LogicTree) {
-		super(tree);
-	}
-
-	override function get(from: Int): Dynamic {
-		var object: Object = inputs[0].get();
-		var slot: Int = inputs[1].get();
-
-		if (object == null) return null;
-
-	#if lnx_particles
-
-		var mo = cast(object, iron.object.MeshObject);
-
-		var psys = mo.particleSystems != null ? mo.particleSystems[slot] : 
-			mo.particleOwner != null && mo.particleOwner.particleSystems != null ? mo.particleOwner.particleSystems[slot] : null;
-
-		if (psys == null) return null;
-
-		return switch (from) {
-			case 0:
-				psys.r.name;
-			case 1:
-				psys.r.particle_size;
-			case 2:
-				psys.r.frame_start;
-			case 3:
-				psys.r.frame_end;
-			case 4:
-				psys.lifetime;
-			case 5:
-				psys.r.lifetime;
-			case 6:
-				psys.r.emit_from;
-			case 7:
-				new iron.math.Vec3(psys.alignx*2, psys.aligny*2, psys.alignz*2);
-			case 8:
-				psys.r.factor_random;
-			case 9:
-				new iron.math.Vec3(psys.gx, psys.gy, psys.gz);
-			case 10:
-				psys.r.weight_gravity;
-			case 11:
-				psys.speed;
-			case 12:
-				psys.time;
-			case 13:
-				psys.lap;
-			case 14:
-				psys.lapTime;
-			case 15:
-				psys.count;
-			default: 
-				null;
-		}
-	#end
-
-		return null;
-	}
-}
+package leenkx.logicnode;
+
+import iron.object.Object;
+
+class GetParticleDataNode extends LogicNode {
+
+	public function new(tree: LogicTree) {
+		super(tree);
+	}
+
+	override function get(from: Int): Dynamic {
+		var object: Object = inputs[0].get();
+		var slot: Int = inputs[1].get();
+
+		if (object == null) return null;
+
+	#if lnx_particles
+
+		var mo = cast(object, iron.object.MeshObject);
+
+		var psys = mo.particleSystems != null ? mo.particleSystems[slot] : 
+			mo.particleOwner != null && mo.particleOwner.particleSystems != null ? mo.particleOwner.particleSystems[slot] : null;
+
+		if (psys == null) return null;
+
+		return switch (from) {
+			case 0:
+				@:privateAccess psys.r.name;
+			case 1:
+				@:privateAccess psys.r.particle_size;
+			case 2:
+				@:privateAccess psys.r.frame_start;
+			case 3:
+				@:privateAccess psys.r.frame_end;
+			case 4:
+				@:privateAccess psys.lifetime;
+			case 5:
+				@:privateAccess psys.r.lifetime;
+			case 6:
+				@:privateAccess psys.r.emit_from;
+			case 7:
+				new iron.math.Vec3(@:privateAccess psys.alignx*2, @:privateAccess psys.aligny*2, @:privateAccess psys.alignz*2);
+			case 8:
+				@:privateAccess psys.r.factor_random;
+			case 9:
+				new iron.math.Vec3(@:privateAccess psys.gx, @:privateAccess psys.gy, @:privateAccess psys.gz);
+			case 10:
+				@:privateAccess psys.r.weight_gravity;
+			case 11:
+				psys.speed;
+			case 12:
+				@:privateAccess psys.time;
+			case 13:
+				@:privateAccess psys.lap;
+			case 14:
+				@:privateAccess psys.lapTime;
+			case 15:
+				@:privateAccess psys.count;
+			default: 
+				null;
+		}
+	#end
+
+		return null;
+	}
+}
diff --git a/leenkx/Sources/leenkx/logicnode/GetParticleNode.hx b/leenkx/Sources/leenkx/logicnode/GetParticleNode.hx
index 1a2df24..7b9b9c1 100644
--- a/leenkx/Sources/leenkx/logicnode/GetParticleNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/GetParticleNode.hx
@@ -1,38 +1,38 @@
-package leenkx.logicnode;
-
-import iron.object.Object;
-
-class GetParticleNode extends LogicNode {
-
-	public function new(tree: LogicTree) {
-		super(tree);
-	}
-
-	override function get(from: Int): Dynamic {
-		var object: Object = inputs[0].get();
-
-		if (object == null) return null;
-
-	#if lnx_particles
-
-		var mo = cast(object, iron.object.MeshObject);
-	
-		switch (from) {
-			case 0:
-				var names: Array<String> = [];
-				if (mo.particleSystems != null)
-					for (psys in mo.particleSystems)
-						names.push(psys.r.name);
-				return names;
-			case 1:
-				return mo.particleSystems != null ? mo.particleSystems.length : 0;
-			case 2:
-				return mo.render_emitter;
-			default: 
-				null;
-		}
-	#end
-
-		return null;
-	}
-}
+package leenkx.logicnode;
+
+import iron.object.Object;
+
+class GetParticleNode extends LogicNode {
+
+	public function new(tree: LogicTree) {
+		super(tree);
+	}
+
+	override function get(from: Int): Dynamic {
+		var object: Object = inputs[0].get();
+
+		if (object == null) return null;
+
+	#if lnx_particles
+
+		var mo = cast(object, iron.object.MeshObject);
+	
+		switch (from) {
+			case 0:
+				var names: Array<String> = [];
+				if (mo.particleSystems != null)
+					for (psys in mo.particleSystems)
+						names.push(@:privateAccess psys.r.name);
+				return names;
+			case 1:
+				return mo.particleSystems != null ? mo.particleSystems.length : 0;
+			case 2:
+				return mo.render_emitter;
+			default: 
+				null;
+		}
+	#end
+
+		return null;
+	}
+}
diff --git a/leenkx/Sources/leenkx/logicnode/RemoveParticleFromObjectNode.hx b/leenkx/Sources/leenkx/logicnode/RemoveParticleFromObjectNode.hx
index 17f7ef7..573444f 100644
--- a/leenkx/Sources/leenkx/logicnode/RemoveParticleFromObjectNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/RemoveParticleFromObjectNode.hx
@@ -1,64 +1,64 @@
-package leenkx.logicnode;
-
-import iron.object.Object;
-
-class RemoveParticleFromObjectNode extends LogicNode {
-
-	public var property0: String;
-
-	public function new(tree: LogicTree) {
-		super(tree);
-	}
-
-	override function run(from: Int) {
-		#if lnx_particles
-		var object: Object = inputs[1].get();
-
-		if (object == null) return;
-
-		var mo = cast(object, iron.object.MeshObject);
-
-		if (mo.particleSystems == null) return;
-
-		if (property0 == 'All'){
-			mo.particleSystems = null;
-			for (c in mo.particleChildren) c.remove();
-			mo.particleChildren = null;
-			mo.particleOwner = null;
-			mo.render_emitter = true;
-		} 
-		else {
-			
-			var slot: Int = -1;
-			if (property0 == 'Name'){
-				var name: String = inputs[2].get();
-				for (i => psys in mo.particleSystems){
-					if (psys.r.name == name){ slot = i; break; }
-				}
-			} 
-			else slot = inputs[2].get();
-				
-			if (mo.particleSystems.length > slot){
-				for (i in slot+1...mo.particleSystems.length){
-					var mi = cast(mo.particleChildren[i], iron.object.MeshObject);
-					mi.particleIndex = mi.particleIndex - 1;
-				}
-				mo.particleSystems.splice(slot, 1);
-				mo.particleChildren[slot].remove();
-				mo.particleChildren.splice(slot, 1);
-			}
-
-			if (slot == 0){
-				mo.particleSystems = null;
-				mo.particleChildren = null;
-				mo.particleOwner = null;
-				mo.render_emitter = true;
-			}
-
-		}
-
-		#end
-
-		runOutput(0);
-	}
-}
+package leenkx.logicnode;
+
+import iron.object.Object;
+
+class RemoveParticleFromObjectNode extends LogicNode {
+
+	public var property0: String;
+
+	public function new(tree: LogicTree) {
+		super(tree);
+	}
+
+	override function run(from: Int) {
+		#if lnx_particles
+		var object: Object = inputs[1].get();
+
+		if (object == null) return;
+
+		var mo = cast(object, iron.object.MeshObject);
+
+		if (mo.particleSystems == null) return;
+
+		if (property0 == 'All'){
+			mo.particleSystems = null;
+			for (c in mo.particleChildren) c.remove();
+			mo.particleChildren = null;
+			mo.particleOwner = null;
+			mo.render_emitter = true;
+		} 
+		else {
+			
+			var slot: Int = -1;
+			if (property0 == 'Name'){
+				var name: String = inputs[2].get();
+				for (i => psys in mo.particleSystems){
+					if (@:privateAccess psys.r.name == name){ slot = i; break; }
+				}
+			} 
+			else slot = inputs[2].get();
+				
+			if (mo.particleSystems.length > slot){
+				for (i in slot+1...mo.particleSystems.length){
+					var mi = cast(mo.particleChildren[i], iron.object.MeshObject);
+					mi.particleIndex = mi.particleIndex - 1;
+				}
+				mo.particleSystems.splice(slot, 1);
+				mo.particleChildren[slot].remove();
+				mo.particleChildren.splice(slot, 1);
+			}
+
+			if (slot == 0){
+				mo.particleSystems = null;
+				mo.particleChildren = null;
+				mo.particleOwner = null;
+				mo.render_emitter = true;
+			}
+
+		}
+
+		#end
+
+		runOutput(0);
+	}
+}
diff --git a/leenkx/Sources/leenkx/logicnode/SetParticleDataNode.hx b/leenkx/Sources/leenkx/logicnode/SetParticleDataNode.hx
index acf6071..6b80f20 100644
--- a/leenkx/Sources/leenkx/logicnode/SetParticleDataNode.hx
+++ b/leenkx/Sources/leenkx/logicnode/SetParticleDataNode.hx
@@ -1,75 +1,75 @@
-package leenkx.logicnode;
-
-import iron.object.Object;
-
-class SetParticleDataNode extends LogicNode {
-
-	public var property0: String;
-
-	public function new(tree: LogicTree) {
-		super(tree);
-	}
-
-	override function run(from: Int) {
-		#if lnx_particles
-		var object: Object = inputs[1].get();
-		var slot: Int = inputs[2].get();
-
-		if (object == null) return;
-
-		var mo = cast(object, iron.object.MeshObject);
-
-		var psys = mo.particleSystems != null ? mo.particleSystems[slot] : 
-			mo.particleOwner != null && mo.particleOwner.particleSystems != null ? mo.particleOwner.particleSystems[slot] : null;		if (psys == null) return;
-
-		switch (property0) {
-			case 'Particle Size':
-				psys.r.particle_size = inputs[3].get();
-			case 'Frame Start':
-				psys.r.frame_start = inputs[3].get();
-				psys.animtime = (psys.r.frame_end - psys.r.frame_start) / psys.frameRate;
-				psys.spawnRate = ((psys.r.frame_end - psys.r.frame_start) / psys.count) / psys.frameRate;
-			case 'Frame End':
-				psys.r.frame_end = inputs[3].get();
-				psys.animtime = (psys.r.frame_end - psys.r.frame_start) / psys.frameRate;
-				psys.spawnRate = ((psys.r.frame_end - psys.r.frame_start) / psys.count) / psys.frameRate;
-			case 'Lifetime':
-				psys.lifetime = inputs[3].get() / psys.frameRate;
-			case 'Lifetime Random':
-				psys.r.lifetime_random = inputs[3].get();
-			case 'Emit From':
-				var emit_from: Int = inputs[3].get();
-				if (emit_from == 0 || emit_from == 1 || emit_from == 2) {
-					psys.r.emit_from = emit_from;
-					psys.setupGeomGpu(mo.particleChildren != null ? mo.particleChildren[slot] : cast(iron.Scene.active.getChild(psys.data.raw.instance_object), iron.object.MeshObject), mo);
-				}
-			case 'Velocity':
-				var vel: iron.math.Vec3 = inputs[3].get();
-				psys.alignx = vel.x / 2;
-				psys.aligny = vel.y / 2;
-				psys.alignz = vel.z / 2;
-			case 'Velocity Random':
-				psys.r.factor_random = inputs[3].get();
-			case 'Weight Gravity':
-				psys.r.weight_gravity = inputs[3].get();
-				if (iron.Scene.active.raw.gravity != null) {
-					psys.gx = iron.Scene.active.raw.gravity[0] * psys.r.weight_gravity;
-					psys.gy = iron.Scene.active.raw.gravity[1] * psys.r.weight_gravity;
-					psys.gz = iron.Scene.active.raw.gravity[2] * psys.r.weight_gravity;
-				}
-				else {
-					psys.gx = 0;
-					psys.gy = 0;
-					psys.gz = -9.81 * psys.r.weight_gravity;
-				}
-			case 'Speed':
-				psys.speed = inputs[3].get();
-			default: 
-				null;
-		}
-
-		#end
-
-		runOutput(0);
-	}
-}
+package leenkx.logicnode;
+
+import iron.object.Object;
+
+class SetParticleDataNode extends LogicNode {
+
+	public var property0: String;
+
+	public function new(tree: LogicTree) {
+		super(tree);
+	}
+
+	override function run(from: Int) {
+		#if lnx_particles
+		var object: Object = inputs[1].get();
+		var slot: Int = inputs[2].get();
+
+		if (object == null) return;
+
+		var mo = cast(object, iron.object.MeshObject);
+
+		var psys = mo.particleSystems != null ? mo.particleSystems[slot] : 
+			mo.particleOwner != null && mo.particleOwner.particleSystems != null ? mo.particleOwner.particleSystems[slot] : null;		if (psys == null) return;
+
+		switch (property0) {
+			case 'Particle Size':
+				@:privateAccess psys.r.particle_size = inputs[3].get();
+			case 'Frame Start':
+				@:privateAccess psys.r.frame_start = inputs[3].get();
+				@:privateAccess psys.animtime = (@:privateAccess psys.r.frame_end - @:privateAccess psys.r.frame_start) / @:privateAccess psys.frameRate;
+				@:privateAccess psys.spawnRate = ((@:privateAccess psys.r.frame_end - @:privateAccess psys.r.frame_start) / @:privateAccess psys.count) / @:privateAccess psys.frameRate;
+			case 'Frame End':
+				@:privateAccess psys.r.frame_end = inputs[3].get();
+				@:privateAccess psys.animtime = (@:privateAccess psys.r.frame_end - @:privateAccess psys.r.frame_start) / @:privateAccess psys.frameRate;
+				@:privateAccess psys.spawnRate = ((@:privateAccess psys.r.frame_end - @:privateAccess psys.r.frame_start) / @:privateAccess psys.count) / @:privateAccess psys.frameRate;
+			case 'Lifetime':
+				@:privateAccess psys.lifetime = inputs[3].get() / @:privateAccess psys.frameRate;
+			case 'Lifetime Random':
+				@:privateAccess psys.r.lifetime_random = inputs[3].get();
+			case 'Emit From':
+				var emit_from: Int = inputs[3].get();
+				if (emit_from == 0 || emit_from == 1 || emit_from == 2) {
+					@:privateAccess psys.r.emit_from = emit_from;
+					@:privateAccess psys.setupGeomGpu(mo.particleChildren != null ? mo.particleChildren[slot] : cast(iron.Scene.active.getChild(psys.data.raw.instance_object), iron.object.MeshObject), mo);
+				}
+			case 'Velocity':
+				var vel: iron.math.Vec3 = inputs[3].get();
+				@:privateAccess psys.alignx = vel.x / 2;
+				@:privateAccess psys.aligny = vel.y / 2;
+				@:privateAccess psys.alignz = vel.z / 2;
+			case 'Velocity Random':
+				psys.r.factor_random = inputs[3].get();
+			case 'Weight Gravity':
+				psys.r.weight_gravity = inputs[3].get();
+				if (iron.Scene.active.raw.gravity != null) {
+					@:privateAccess psys.gx = iron.Scene.active.raw.gravity[0] * @:privateAccess psys.r.weight_gravity;
+					@:privateAccess psys.gy = iron.Scene.active.raw.gravity[1] * @:privateAccess psys.r.weight_gravity;
+					@:privateAccess psys.gz = iron.Scene.active.raw.gravity[2] * @:privateAccess psys.r.weight_gravity;
+				}
+				else {
+					@:privateAccess psys.gx = 0;
+					@:privateAccess psys.gy = 0;
+					@:privateAccess psys.gz = -9.81 * @:privateAccess psys.r.weight_gravity;
+				}
+			case 'Speed':
+				psys.speed = inputs[3].get();
+			default: 
+				null;
+		}
+
+		#end
+
+		runOutput(0);
+	}
+}
diff --git a/leenkx/Sources/leenkx/trait/physics/bullet/PhysicsWorld.hx b/leenkx/Sources/leenkx/trait/physics/bullet/PhysicsWorld.hx
index e2bea17..74dd869 100644
--- a/leenkx/Sources/leenkx/trait/physics/bullet/PhysicsWorld.hx
+++ b/leenkx/Sources/leenkx/trait/physics/bullet/PhysicsWorld.hx
@@ -101,7 +101,7 @@ class PhysicsWorld extends Trait {
 
 
 
-	public function new(timeScale = 1.0, maxSteps = 10, solverIterations = 10, debugDrawMode: DebugDrawMode = NoDebug) {
+	public function new(timeScale = 1.0, maxSteps = 10, solverIterations = 10, fixedStep = 1 / 60, debugDrawMode: DebugDrawMode = NoDebug) {
 		super();
 
 		if (nullvec) {
@@ -120,6 +120,7 @@ class PhysicsWorld extends Trait {
 		this.timeScale = timeScale;
 		this.maxSteps = maxSteps;
 		this.solverIterations = solverIterations;
+		Time.initFixedStep(fixedStep);
 
 		// First scene
 		if (active == null) {
@@ -136,10 +137,10 @@ class PhysicsWorld extends Trait {
 		conMap = new Map();
 		active = this;
 
-		// Ensure physics are updated first in the lateUpdate list
-		_lateUpdate = [lateUpdate];
-		@:privateAccess iron.App.traitLateUpdates.insert(0, lateUpdate);
-
+		// Ensure physics are updated first in the fixedUpdate list
+		_fixedUpdate = [fixedUpdate];
+		@:privateAccess iron.App.traitFixedUpdates.insert(0, fixedUpdate);
+		
 		setDebugDrawMode(debugDrawMode);
 
 		iron.Scene.active.notifyOnRemove(function() {
@@ -298,8 +299,8 @@ class PhysicsWorld extends Trait {
 		return rb;
 	}
 
-	function lateUpdate() {
-		var t = Time.delta * timeScale;
+	function fixedUpdate() {
+		var t = Time.fixedStep * timeScale * Time.scale;
 		if (t == 0.0) return; // Simulation paused
 
 		#if lnx_debug
@@ -308,13 +309,10 @@ class PhysicsWorld extends Trait {
 
 		if (preUpdates != null) for (f in preUpdates) f();
 
-		//Bullet physics fixed timescale
-		var fixedTime = 1.0 / 60;
-
 		//This condition must be satisfied to not loose time
-		var currMaxSteps = t < (fixedTime * maxSteps) ? maxSteps : 1;
+		var currMaxSteps = t < (Time.fixedStep * maxSteps) ? maxSteps : 1;
 
-		world.stepSimulation(t, currMaxSteps, fixedTime);
+		world.stepSimulation(t, currMaxSteps, Time.fixedStep);
 		updateContacts();
 
 		for (rb in rbMap) @:privateAccess rb.physicsUpdate();
diff --git a/leenkx/Sources/leenkx/trait/physics/bullet/RigidBody.hx b/leenkx/Sources/leenkx/trait/physics/bullet/RigidBody.hx
index b023509..a84d758 100644
--- a/leenkx/Sources/leenkx/trait/physics/bullet/RigidBody.hx
+++ b/leenkx/Sources/leenkx/trait/physics/bullet/RigidBody.hx
@@ -2,11 +2,13 @@ package leenkx.trait.physics.bullet;
 
 #if lnx_bullet
 
+import leenkx.math.Helper;
+import iron.data.MeshData;
 import iron.math.Vec4;
 import iron.math.Quat;
 import iron.object.Transform;
 import iron.object.MeshObject;
-import iron.data.MeshData;
+import iron.system.Time;
 
 /**
    RigidBody is used to allow objects to interact with Physics in your game including collisions and gravity.
@@ -76,6 +78,14 @@ class RigidBody extends iron.Trait {
 	static var triangleMeshCache = new Map<MeshData, bullet.Bt.TriangleMesh>();
 	static var usersCache = new Map<MeshData, Int>();
 
+	// Interpolation
+	var interpolate: Bool = false;
+	var time: Float = 0.0;
+	var currentPos: bullet.Bt.Vector3 = new bullet.Bt.Vector3(0, 0, 0);
+	var prevPos: bullet.Bt.Vector3 = new bullet.Bt.Vector3(0, 0, 0);
+	var currentRot: bullet.Bt.Quaternion = new bullet.Bt.Quaternion(0, 0, 0, 1);
+	var prevRot: bullet.Bt.Quaternion = new bullet.Bt.Quaternion(0, 0, 0, 1);
+
 	public function new(shape = Shape.Box, mass = 1.0, friction = 0.5, restitution = 0.0, group = 1, mask = 1,
 						params: RigidBodyParams = null, flags: RigidBodyFlags = null) {
 		super();
@@ -85,7 +95,7 @@ class RigidBody extends iron.Trait {
 			vec1 = new bullet.Bt.Vector3(0, 0, 0);
 			vec2 = new bullet.Bt.Vector3(0, 0, 0);
 			vec3 = new bullet.Bt.Vector3(0, 0, 0);
-			quat1 = new bullet.Bt.Quaternion(0, 0, 0, 0);
+			quat1 = new bullet.Bt.Quaternion(0, 0, 0, 1);
 			trans1 = new bullet.Bt.Transform();
 			trans2 = new bullet.Bt.Transform();
 		}
@@ -117,6 +127,7 @@ class RigidBody extends iron.Trait {
 			animated: false,
 			trigger: false,
 			ccd: false,
+			interpolate: false,
 			staticObj: false,
 			useDeactivation: true
 		};
@@ -131,6 +142,7 @@ class RigidBody extends iron.Trait {
 		this.animated = flags.animated;
 		this.trigger = flags.trigger;
 		this.ccd = flags.ccd;
+		this.interpolate = flags.interpolate;
 		this.staticObj = flags.staticObj;
 		this.useDeactivation = flags.useDeactivation;
 
@@ -153,6 +165,7 @@ class RigidBody extends iron.Trait {
 		if (!Std.isOfType(object, MeshObject)) return; // No mesh data
 
 		transform = object.transform;
+		transform.buildMatrix();
 		physics = leenkx.trait.physics.PhysicsWorld.active;
 
 		if (shape == Shape.Box) {
@@ -244,6 +257,9 @@ class RigidBody extends iron.Trait {
 		quat1.setValue(quat.x, quat.y, quat.z, quat.w);
 		trans1.setRotation(quat1);
 
+		currentPos.setValue(vec1.x(), vec1.y(), vec1.z());
+		currentRot.setValue(quat.x, quat.y, quat.z, quat.w);
+
 		var centerOfMassOffset = trans2;
 		centerOfMassOffset.setIdentity();
 		motionState = new bullet.Bt.DefaultMotionState(trans1, centerOfMassOffset);
@@ -307,7 +323,8 @@ class RigidBody extends iron.Trait {
 
 		physics.addRigidBody(this);
 		notifyOnRemove(removeFromWorld);
-
+		if (!animated) notifyOnUpdate(update);
+		
 		if (onReady != null) onReady();
 
 		#if js
@@ -317,26 +334,71 @@ class RigidBody extends iron.Trait {
 		#end
 	}
 
+
+	function update() {
+		if (interpolate) {
+			time += Time.delta;
+
+			while (time >= Time.fixedStep) {
+				time -= Time.fixedStep;
+			}
+
+			var t: Float = time / Time.fixedStep;
+			t = Helper.clamp(t, 0, 1);
+
+			var tx: Float = prevPos.x() * (1.0 - t) + currentPos.x() * t;
+			var ty: Float = prevPos.y() * (1.0 - t) + currentPos.y() * t;
+			var tz: Float = prevPos.z() * (1.0 - t) + currentPos.z() * t;
+
+			var tRot: bullet.Bt.Quaternion = nlerp(prevRot, currentRot, t);
+
+			transform.loc.set(tx, ty, tz, 1.0);
+			transform.rot.set(tRot.x(), tRot.y(), tRot.z(), tRot.w());
+		} else {
+			transform.loc.set(currentPos.x(), currentPos.y(), currentPos.z(), 1.0);
+			transform.rot.set(currentRot.x(), currentRot.y(), currentRot.z(), currentRot.w());
+		}
+
+		if (object.parent != null) {
+			var ptransform = object.parent.transform;
+			transform.loc.x -= ptransform.worldx();
+			transform.loc.y -= ptransform.worldy();
+			transform.loc.z -= ptransform.worldz();
+		}
+
+		transform.buildMatrix();
+	}
+
+	function nlerp(q1: bullet.Bt.Quaternion, q2: bullet.Bt.Quaternion, t: Float): bullet.Bt.Quaternion {
+		var dot = q1.x() * q2.x() + q1.y() * q2.y() + q1.z() * q2.z() + q1.w() * q2.w();
+		var _q2 = dot < 0 ? new bullet.Bt.Quaternion(-q2.x(), -q2.y(), -q2.z(), -q2.w()) : q2;
+
+		var x = q1.x() * (1.0 - t) + _q2.x() * t;
+		var y = q1.y() * (1.0 - t) + _q2.y() * t;
+		var z = q1.z() * (1.0 - t) + _q2.z() * t;
+		var w = q1.w() * (1.0 - t) + _q2.w() * t;
+
+		var len = Math.sqrt(x * x + y * y + z * z + w * w);
+		return new bullet.Bt.Quaternion(x / len, y / len, z / len, w / len);
+	}
+	
 	function physicsUpdate() {
 		if (!ready) return;
 		if (animated) {
 			syncTransform();
-		}
-		else {
+		} else {
+			if (interpolate) {
+				prevPos.setValue(currentPos.x(), currentPos.y(), currentPos.z());
+				prevRot.setValue(currentRot.x(), currentRot.y(), currentRot.z(), currentRot.w());
+			}
 			var trans = body.getWorldTransform();
 			var p = trans.getOrigin();
 			var q = trans.getRotation();
-
-			transform.loc.set(p.x(), p.y(), p.z());
-			transform.rot.set(q.x(), q.y(), q.z(), q.w());
-			if (object.parent != null) {
-				var ptransform = object.parent.transform;
-				transform.loc.x -= ptransform.worldx();
-				transform.loc.y -= ptransform.worldy();
-				transform.loc.z -= ptransform.worldz();
-			}
 			transform.clearDelta();
-			transform.buildMatrix();
+			// transform.buildMatrix();
+			currentPos.setValue(p.x(), p.y(), p.z());
+			currentRot.setValue(q.x(), q.y(), q.z(), q.w());
+
 
 			#if hl
 			p.delete();
@@ -689,6 +751,7 @@ typedef RigidBodyFlags = {
 	var animated: Bool;
 	var trigger: Bool;
 	var ccd: Bool;
+	var interpolate: Bool;
 	var staticObj: Bool;
 	var useDeactivation: Bool;
 }
diff --git a/leenkx/blender/lnx/exporter.py b/leenkx/blender/lnx/exporter.py
index ffb2434..c35de79 100644
--- a/leenkx/blender/lnx/exporter.py
+++ b/leenkx/blender/lnx/exporter.py
@@ -2297,6 +2297,8 @@ class LeenkxExporter:
             out_particlesys = {
                 'name': particleRef[1]["structName"],
                 'type': 0 if psettings.type == 'EMITTER' else 1, # HAIR
+                'auto_start': psettings.lnx_auto_start,
+                'is_unique': psettings.lnx_is_unique,
                 'loop': psettings.lnx_loop,
                 # Emission
                 'count': int(psettings.count * psettings.lnx_count_mult),
@@ -2813,6 +2815,7 @@ class LeenkxExporter:
             body_flags['animated'] = rb.kinematic
             body_flags['trigger'] = bobject.lnx_rb_trigger
             body_flags['ccd'] = bobject.lnx_rb_ccd
+            body_flags['interpolate'] = bobject.lnx_rb_interpolate
             body_flags['staticObj'] = is_static
             body_flags['useDeactivation'] = rb.use_deactivation
             x['parameters'].append(lnx.utils.get_haxe_json_string(body_params))
@@ -3037,7 +3040,7 @@ class LeenkxExporter:
 
             rbw = self.scene.rigidbody_world
             if rbw is not None and rbw.enabled:
-                out_trait['parameters'] = [str(rbw.time_scale), str(rbw.substeps_per_frame), str(rbw.solver_iterations)]
+                out_trait['parameters'] = [str(rbw.time_scale), str(rbw.substeps_per_frame), str(rbw.solver_iterations), str(wrd.lnx_physics_fixed_step)]
 
                 if phys_pkg == 'bullet' or phys_pkg == 'oimo':
                     debug_draw_mode = 1 if wrd.lnx_physics_dbg_draw_wireframe else 0
diff --git a/leenkx/blender/lnx/handlers.py b/leenkx/blender/lnx/handlers.py
index 80cbdb5..ef47589 100644
--- a/leenkx/blender/lnx/handlers.py
+++ b/leenkx/blender/lnx/handlers.py
@@ -87,6 +87,7 @@ def on_operator_post(operator_id: str) -> None:
             target_obj.lnx_rb_trigger = source_obj.lnx_rb_trigger
             target_obj.lnx_rb_deactivation_time = source_obj.lnx_rb_deactivation_time
             target_obj.lnx_rb_ccd = source_obj.lnx_rb_ccd
+            target_obj.lnx_rb_interpolate = source_obj.lnx_rb_interpolate
             target_obj.lnx_rb_collision_filter_mask = source_obj.lnx_rb_collision_filter_mask
 
     elif operator_id == "NODE_OT_new_node_tree":
diff --git a/leenkx/blender/lnx/material/cycles_nodes/nodes_converter.py b/leenkx/blender/lnx/material/cycles_nodes/nodes_converter.py
index 49cb131..5df58ec 100644
--- a/leenkx/blender/lnx/material/cycles_nodes/nodes_converter.py
+++ b/leenkx/blender/lnx/material/cycles_nodes/nodes_converter.py
@@ -82,28 +82,37 @@ def parse_clamp(node: bpy.types.ShaderNodeClamp, out_socket: bpy.types.NodeSocke
 
 
 def parse_valtorgb(node: bpy.types.ShaderNodeValToRGB, out_socket: bpy.types.NodeSocket, state: ParserState) -> Union[floatstr, vec3str]:
-    # Alpha (TODO: make ColorRamp calculation vec4-based and split afterwards)
-    if out_socket == node.outputs[1]:
-        return '1.0'
 
     input_fac: bpy.types.NodeSocket = node.inputs[0]
-
+    alpha_out = out_socket == node.outputs[1]
     fac: str = c.parse_value_input(input_fac) if input_fac.is_linked else c.to_vec1(input_fac.default_value)
     interp = node.color_ramp.interpolation
     elems = node.color_ramp.elements
-
+    
     if len(elems) == 1:
-        return c.to_vec3(elems[0].color)
-
-    # Write color array
-    # The last entry is included twice so that the interpolation
-    # between indices works (no out of bounds error)
-    cols_var = c.node_name(node.name).upper() + '_COLS'
+        if alpha_out:
+            return c.to_vec1(elems[0].color[3])  # Return alpha from the color
+        else:
+            return c.to_vec3(elems[0].color)  # Return RGB
+    
+    name_prefix = c.node_name(node.name).upper()
+    
+    if alpha_out:
+        cols_var = name_prefix + '_ALPHAS'
+    else:
+        cols_var = name_prefix + '_COLS'
 
     if state.current_pass == ParserPass.REGULAR:
-        cols_entries = ', '.join(f'vec3({elem.color[0]}, {elem.color[1]}, {elem.color[2]})' for elem in elems)
-        cols_entries += f', vec3({elems[len(elems) - 1].color[0]}, {elems[len(elems) - 1].color[1]}, {elems[len(elems) - 1].color[2]})'
-        state.curshader.add_const("vec3", cols_var, cols_entries, array_size=len(elems) + 1)
+        if alpha_out:
+            cols_entries = ', '.join(f'{elem.color[3]}' for elem in elems)
+            # Add last value twice to avoid out of bounds access
+            cols_entries += f', {elems[len(elems) - 1].color[3]}'
+            state.curshader.add_const("float", cols_var, cols_entries, array_size=len(elems) + 1)
+        else:
+            # Create array of RGB values for color output
+            cols_entries = ', '.join(f'vec3({elem.color[0]}, {elem.color[1]}, {elem.color[2]})' for elem in elems)
+            cols_entries += f', vec3({elems[len(elems) - 1].color[0]}, {elems[len(elems) - 1].color[1]}, {elems[len(elems) - 1].color[2]})'
+            state.curshader.add_const("vec3", cols_var, cols_entries, array_size=len(elems) + 1)
 
     fac_var = c.node_name(node.name) + '_fac' + state.get_parser_pass_suffix()
     state.curshader.write(f'float {fac_var} = {fac};')
@@ -121,21 +130,22 @@ def parse_valtorgb(node: bpy.types.ShaderNodeValToRGB, out_socket: bpy.types.Nod
 
     # Linear interpolation
     else:
-        # Write factor array
-        facs_var = c.node_name(node.name).upper() + '_FACS'
+        # Write factor array - same for both color and alpha
+        facs_var = name_prefix + '_FACS'
         if state.current_pass == ParserPass.REGULAR:
             facs_entries = ', '.join(str(elem.position) for elem in elems)
-            # Add one more entry at the rightmost position so that the
-            # interpolation between indices works (no out of bounds error)
+            # Add one more entry at the rightmost position to avoid out of bounds access
             facs_entries += ', 1.0'
             state.curshader.add_const("float", facs_var, facs_entries, array_size=len(elems) + 1)
 
-        # Mix color
+        # Calculation for interpolation position
         prev_stop_fac = f'{facs_var}[{index_var}]'
         next_stop_fac = f'{facs_var}[{index_var} + 1]'
         prev_stop_col = f'{cols_var}[{index_var}]'
         next_stop_col = f'{cols_var}[{index_var} + 1]'
         rel_pos = f'({fac_var} - {prev_stop_fac}) * (1.0 / ({next_stop_fac} - {prev_stop_fac}))'
+        
+        # Use mix function for both alpha and color outputs (mix works on floats too)
         return f'mix({prev_stop_col}, {next_stop_col}, max({rel_pos}, 0.0))'
 
 if bpy.app.version > (3, 2, 0):
diff --git a/leenkx/blender/lnx/material/make_particle.py b/leenkx/blender/lnx/material/make_particle.py
index d22e534..8001dbf 100644
--- a/leenkx/blender/lnx/material/make_particle.py
+++ b/leenkx/blender/lnx/material/make_particle.py
@@ -1,3 +1,4 @@
+import bpy
 import lnx.utils
 import lnx.material.mat_state as mat_state
 
@@ -10,6 +11,48 @@ else:
 
 def write(vert, particle_info=None, shadowmap=False):
 
+    ramp_el_len = 0
+
+    ramp_positions = []
+    ramp_colors_b = []
+    size_over_time_factor = 0
+
+    use_rotations = False
+    rotation_mode = 'NONE'
+    rotation_factor_random = 0
+    phase_factor = 0
+    phase_factor_random = 0
+
+    for obj in bpy.data.objects:
+        for psys in obj.particle_systems:
+            psettings = psys.settings
+
+            if psettings.instance_object:
+                if psettings.instance_object.active_material:
+                    # FIXME: Different particle systems may share the same particle object. This ideally should check the correct `ParticleSystem` using an id or name in the particle's object material.
+                    if psettings.instance_object.active_material.name.replace(".", "_") == vert.context.matname:
+                        # Rotation data
+                        use_rotations = psettings.use_rotations
+                        rotation_mode = psettings.rotation_mode
+                        rotation_factor_random = psettings.rotation_factor_random
+                        phase_factor = psettings.phase_factor
+                        phase_factor_random = psettings.phase_factor_random
+
+                        # Texture slots data
+                        if psettings.texture_slots and len(psettings.texture_slots.items()) != 0:
+                            for tex_slot in psettings.texture_slots:
+                                if not tex_slot: break
+                                if not tex_slot.use_map_size: break # TODO: check also for other influences
+                                if tex_slot.texture and tex_slot.texture.use_color_ramp:
+                                    if tex_slot.texture.color_ramp and tex_slot.texture.color_ramp.elements:
+                                        ramp_el_len = len(tex_slot.texture.color_ramp.elements.items())
+                                        for element in tex_slot.texture.color_ramp.elements:
+                                            ramp_positions.append(element.position)
+                                            ramp_colors_b.append(element.color[2])
+                                        size_over_time_factor = tex_slot.size_factor
+                                        break
+
+
     # Outs
     out_index = True if particle_info != None and particle_info['index'] else False
     out_age = True if particle_info != None and particle_info['age'] else False
@@ -19,19 +62,50 @@ def write(vert, particle_info=None, shadowmap=False):
     out_velocity = True if particle_info != None and particle_info['velocity'] else False
     out_angular_velocity = True if particle_info != None and particle_info['angular_velocity'] else False
 
+    # Force Leenkx to create a new shader per material ID
+    vert.write(f'#ifdef PARTICLE_ID_{vert.context.material.lnx_material_id}')
+    vert.write('#endif')
+
     vert.add_uniform('mat4 pd', '_particleData')
+    vert.add_uniform('float pd_size_random', '_particleSizeRandom')
+    vert.add_uniform('float pd_random', '_particleRandom')
+    vert.add_uniform('float pd_size', '_particleSize')
+
+    if ramp_el_len != 0:
+        vert.add_const('float', 'P_SIZE_OVER_TIME_FACTOR', str(size_over_time_factor))
+        for i in range(ramp_el_len):
+            vert.add_const('float', f'P_RAMP_POSITION_{i}', str(ramp_positions[i]))
+            vert.add_const('float', f'P_RAMP_COLOR_B_{i}', str(ramp_colors_b[i]))
 
     str_tex_hash = "float fhash(float n) { return fract(sin(n) * 43758.5453); }\n"
     vert.add_function(str_tex_hash)
 
+
+    if (ramp_el_len != 0):
+        str_ramp_scale = "float get_ramp_scale(float age) {\n"
+
+        for i in range(ramp_el_len):
+            if i == 0:
+                str_ramp_scale += f"if (age <= P_RAMP_POSITION_{i + 1})"
+            elif i == ramp_el_len - 1:
+                str_ramp_scale += f"return P_RAMP_COLOR_B_{ramp_el_len - 1};"
+                break
+            else:
+                str_ramp_scale += f"else if (age <= P_RAMP_POSITION_{i + 1})"
+            str_ramp_scale += f""" {{
+                float t = (age - P_RAMP_POSITION_{i}) / (P_RAMP_POSITION_{i + 1} - P_RAMP_POSITION_{i});
+                return mix(P_RAMP_COLOR_B_{i}, P_RAMP_COLOR_B_{i + 1}, t);
+            }}
+            """
+        str_ramp_scale += "}\n"
+        vert.add_function(str_ramp_scale)
+
     prep = 'float '
     if out_age:
         prep = ''
         vert.add_out('float p_age')
     # var p_age = lapTime - p.i * spawnRate
     vert.write(prep + 'p_age = pd[3][3] - gl_InstanceID * pd[0][1];')
-    # p_age -= p_age * fhash(i) * r.lifetime_random;
-    vert.write('p_age -= p_age * fhash(gl_InstanceID) * pd[2][3];')
 
     # Loop
     # pd[0][0] - animtime, loop stored in sign
@@ -43,13 +117,18 @@ def write(vert, particle_info=None, shadowmap=False):
     if out_lifetime:
         prep = ''
         vert.add_out('float p_lifetime')
-    vert.write(prep + 'p_lifetime = pd[0][2];')
+    vert.write(prep + 'p_lifetime = pd[0][2] * (1 - (fhash(gl_InstanceID + 4 * pd[0][3] + pd_random) * pd[2][3]));')
     # clip with nan
     vert.write('if (p_age < 0 || p_age > p_lifetime) {')
     vert.write('    gl_Position /= 0.0;')
     vert.write('    return;')
     vert.write('}')
 
+    if (ramp_el_len != 0):
+        vert.write('float n_age = clamp(p_age / p_lifetime, 0.0, 1.0);')
+        vert.write(f'spos.xyz *= 1 + (get_ramp_scale(n_age) - 1) * {size_over_time_factor};')
+    vert.write('spos.xyz *= 1 - (fhash(gl_InstanceID + 3 * pd[0][3] + pd_random) * pd_size_random);')
+
     # vert.write('p_age /= 2;') # Match
 
     # object_align_factor / 2 + gxyz
@@ -57,20 +136,20 @@ def write(vert, particle_info=None, shadowmap=False):
     if out_velocity:
         prep = ''
         vert.add_out('vec3 p_velocity')
-    vert.write(prep + 'p_velocity = vec3(pd[1][0], pd[1][1], pd[1][2]);')
+    vert.write(prep + 'p_velocity = vec3(pd[1][0] * (1 / pd_size), pd[1][1] * (1 / pd_size), pd[1][2] * (1 / pd_size));')
 
-    vert.write('p_velocity.x += fhash(gl_InstanceID)                * pd[1][3] - pd[1][3] / 2;')
-    vert.write('p_velocity.y += fhash(gl_InstanceID +     pd[0][3]) * pd[1][3] - pd[1][3] / 2;')
-    vert.write('p_velocity.z += fhash(gl_InstanceID + 2 * pd[0][3]) * pd[1][3] - pd[1][3] / 2;')
+    vert.write('p_velocity.x += (fhash(gl_InstanceID + pd_random)                * 2.0 / pd_size - 1.0 / pd_size) * pd[1][3];')
+    vert.write('p_velocity.y += (fhash(gl_InstanceID + pd_random +     pd[0][3]) * 2.0 / pd_size - 1.0 / pd_size) * pd[1][3];')
+    vert.write('p_velocity.z += (fhash(gl_InstanceID + pd_random + 2 * pd[0][3]) * 2.0 / pd_size - 1.0 / pd_size) * pd[1][3];')
 
     # factor_random = pd[1][3]
     # p.i = gl_InstanceID
     # particles.length = pd[0][3]
 
     # gxyz
-    vert.write('p_velocity.x += (pd[2][0] * p_age) / 5;')
-    vert.write('p_velocity.y += (pd[2][1] * p_age) / 5;')
-    vert.write('p_velocity.z += (pd[2][2] * p_age) / 5;')
+    vert.write('p_velocity.x += (pd[2][0] / (2 * pd_size)) * p_age;')
+    vert.write('p_velocity.y += (pd[2][1] / (2 * pd_size)) * p_age;')
+    vert.write('p_velocity.z += (pd[2][2] / (2 * pd_size)) * p_age;')
 
     prep = 'vec3 '
     if out_location:
@@ -80,6 +159,96 @@ def write(vert, particle_info=None, shadowmap=False):
 
     vert.write('spos.xyz += p_location;')
 
+    # Rotation
+    if use_rotations:
+        if rotation_mode != 'NONE':
+            vert.write(f'float p_angle = ({phase_factor} + (fhash(gl_InstanceID + pd_random + 5 * pd[0][3])) * {phase_factor_random});')
+            vert.write('p_angle *= 3.141592;')
+            vert.write('float c = cos(p_angle);')
+            vert.write('float s = sin(p_angle);')
+            vert.write('vec3 center = spos.xyz - p_location;')
+
+            match rotation_mode:
+                case 'OB_X':
+                    vert.write('vec3 rz = vec3(center.y, -center.x, center.z);')
+                    vert.write('vec2 rotation = vec2(rz.y * c - rz.z * s, rz.y * s + rz.z * c);')
+                    vert.write('spos.xyz = vec3(rz.x, rotation.x, rotation.y) + p_location;')
+
+                    if (not shadowmap):
+                        vert.write('wnormal = vec3(wnormal.y, -wnormal.x, wnormal.z);')
+                        vert.write('vec2 n_rot = vec2(wnormal.y * c - wnormal.z * s, wnormal.y * s + wnormal.z * c);')
+                        vert.write('wnormal = normalize(vec3(wnormal.x, n_rot.x, n_rot.y));')
+                case 'OB_Y':
+                    vert.write('vec2 rotation = vec2(center.x * c + center.z * s, -center.x * s + center.z * c);')
+                    vert.write('spos.xyz = vec3(rotation.x, center.y, rotation.y) + p_location;')
+
+                    if (not shadowmap):
+                        vert.write('wnormal = normalize(vec3(wnormal.x * c + wnormal.z * s, wnormal.y, -wnormal.x * s + wnormal.z * c));')
+                case 'OB_Z':
+                    vert.write('vec3 rz = vec3(center.y, -center.x, center.z);')
+                    vert.write('vec3 ry = vec3(-rz.z, rz.y, rz.x);')
+                    vert.write('vec2 rotation = vec2(ry.x * c - ry.y * s, ry.x * s + ry.y * c);')
+                    vert.write('spos.xyz = vec3(rotation.x, rotation.y, ry.z) + p_location;')
+
+                    if (not shadowmap):
+                        vert.write('wnormal = vec3(wnormal.y, -wnormal.x, wnormal.z);')
+                        vert.write('wnormal = vec3(-wnormal.z, wnormal.y, wnormal.x);')
+                        vert.write('vec2 n_rot = vec2(wnormal.x * c - wnormal.y * s, wnormal.x * s + wnormal.y * c);')
+                        vert.write('wnormal = normalize(vec3(n_rot.x, n_rot.y, wnormal.z));')
+                case 'VEL':
+                    vert.write('vec3 forward = -normalize(p_velocity);')
+                    vert.write('if (length(forward) > 1e-5) {')
+                    vert.write('vec3 world_up = vec3(0.0, 0.0, 1.0);')
+
+                    vert.write('if (abs(dot(forward, world_up)) > 0.999) {')
+                    vert.write('world_up = vec3(-1.0, 0.0, 0.0);')
+                    vert.write('}')
+
+                    vert.write('vec3 right = cross(world_up, forward);')
+                    vert.write('if (length(right) < 1e-5) {')
+                    vert.write('forward = -forward;')
+                    vert.write('right = cross(world_up, forward);')
+                    vert.write('}')
+                    vert.write('right = normalize(right);')
+                    vert.write('vec3 up = normalize(cross(forward, right));')
+
+                    vert.write('mat3 rot = mat3(right, -forward, up);')
+                    vert.write('mat3 phase = mat3(vec3(c, 0.0, -s), vec3(0.0, 1.0, 0.0), vec3(s, 0.0, c));')
+                    vert.write('mat3 final_rot = rot * phase;')
+                    vert.write('spos.xyz = final_rot * center + p_location;')
+
+                    if (not shadowmap):
+                        vert.write('wnormal = normalize(final_rot * wnormal);')
+                    vert.write('}')
+
+            if rotation_factor_random != 0:
+                str_rotate_around = '''vec3 rotate_around(vec3 v, vec3 angle) {
+                    // Rotate around X
+                    float cx = cos(angle.x);
+                    float sx = sin(angle.x);
+                    v = vec3(v.x, v.y * cx - v.z * sx, v.y * sx + v.z * cx);
+                    // Rotate around Y
+                    float cy = cos(angle.y);
+                    float sy = sin(angle.y);
+                    v = vec3(v.x * cy + v.z * sy, v.y, -v.x * sy + v.z * cy);
+                    // Rotate around Z
+                    float cz = cos(angle.z);
+                    float sz = sin(angle.z);
+                    v = vec3(v.x * cz - v.y * sz, v.x * sz + v.y * cz, v.z);
+                    return v;
+                }'''
+                vert.add_function(str_rotate_around)
+
+                vert.write(f'''vec3 r_angle = vec3((fhash(gl_InstanceID + pd_random + 6 * pd[0][3]) * 4 - 2) * {rotation_factor_random},
+                           (fhash(gl_InstanceID + pd_random + 7 * pd[0][3]) * 4 - 2) * {rotation_factor_random},
+                           (fhash(gl_InstanceID + pd_random + 8 * pd[0][3]) * 4 - 2) * {rotation_factor_random});''')
+                vert.write('vec3 r_center = spos.xyz - p_location;')
+                vert.write('r_center = rotate_around(r_center, r_angle);')
+                vert.write('spos.xyz = r_center + p_location;')
+
+                if not shadowmap:
+                    vert.write('wnormal = normalize(rotate_around(wnormal, r_angle));')
+
     # Particle fade
     if mat_state.material.lnx_particle_flag and lnx.utils.get_rp().lnx_particles == 'On' and mat_state.material.lnx_particle_fade:
         vert.add_out('float p_fade')
diff --git a/leenkx/blender/lnx/material/make_shader.py b/leenkx/blender/lnx/material/make_shader.py
index 89f4fe9..8fd4dda 100644
--- a/leenkx/blender/lnx/material/make_shader.py
+++ b/leenkx/blender/lnx/material/make_shader.py
@@ -209,8 +209,7 @@ def make_instancing_and_skinning(mat: Material, mat_users: Dict[Material, List[O
                     global_elems.append({'name': 'ipos', 'data': 'float3'})
                     if 'Rot' in inst:
                         global_elems.append({'name': 'irot', 'data': 'float3'})
-                    #HACK: checking `mat.arm_particle_flag` to force appending 'iscl' to the particle's vertex shader
-                    if 'Scale' in inst or mat.arm_particle_flag:
+                    if 'Scale' in inst:
                         global_elems.append({'name': 'iscl', 'data': 'float3'})
 
             elif inst == 'Off':
diff --git a/leenkx/blender/lnx/props.py b/leenkx/blender/lnx/props.py
index 23be0a8..211c273 100644
--- a/leenkx/blender/lnx/props.py
+++ b/leenkx/blender/lnx/props.py
@@ -197,6 +197,10 @@ def init_properties():
         items=[('Bullet', 'Bullet', 'Bullet'),
                ('Oimo', 'Oimo', 'Oimo')],
         name="Physics Engine", default='Bullet', update=assets.invalidate_compiler_cache)
+    bpy.types.World.lnx_physics_fixed_step = FloatProperty(
+        name="Fixed Step", default=1/60, min=0, max=1,
+        description="Physics steps for fixed update"
+    )
     bpy.types.World.lnx_physics_dbg_draw_wireframe = BoolProperty(
         name="Collider Wireframes", default=False,
         description="Draw wireframes of the physics collider meshes and suspensions of raycast vehicle simulations"
@@ -357,6 +361,7 @@ def init_properties():
     bpy.types.Object.lnx_rb_trigger = BoolProperty(name="Trigger", description="Disable contact response", default=False)
     bpy.types.Object.lnx_rb_deactivation_time = FloatProperty(name="Deactivation Time", description="Delay putting rigid body into sleep", default=0.0)
     bpy.types.Object.lnx_rb_ccd = BoolProperty(name="Continuous Collision Detection", description="Improve collision for fast moving objects", default=False)
+    bpy.types.Object.lnx_rb_interpolate = BoolProperty(name="Interpolation", description="Smooths out the object's transform on physics steps", default=False)
     bpy.types.Object.lnx_rb_collision_filter_mask = bpy.props.BoolVectorProperty(
             name="Collision Collections Filter Mask",
             description="Collision collections rigid body interacts with",
@@ -541,8 +546,10 @@ def init_properties():
     bpy.types.Node.lnx_watch = BoolProperty(name="Watch", description="Watch value of this node in debug console", default=False)
     bpy.types.Node.lnx_version = IntProperty(name="Node Version", description="The version of an instanced node", default=0)
     # Particles
-    bpy.types.ParticleSettings.lnx_count_mult = FloatProperty(name="Multiply Count", description="Multiply particle count when rendering in Leenkx", default=1.0)
+    bpy.types.ParticleSettings.lnx_auto_start = BoolProperty(name="Auto Start", description="Automatically start this particle system on load", default=True)
+    bpy.types.ParticleSettings.lnx_is_unique = BoolProperty(name="Is Unique", description="Make this particle system look different each time it starts", default=False)
     bpy.types.ParticleSettings.lnx_loop = BoolProperty(name="Loop", description="Loop this particle system", default=False)
+    bpy.types.ParticleSettings.lnx_count_mult = FloatProperty(name="Multiply Count", description="Multiply particle count when rendering in Leenkx", default=1.0)
     # Actions
     bpy.types.Action.lnx_root_motion_pos = BoolProperty(name="Root Motion Position", description="Enable position root motion", default=False)
     bpy.types.Action.lnx_root_motion_rot = BoolProperty(name="Root Motion Rotation", description="Enable rotation root motion", default=False)
diff --git a/leenkx/blender/lnx/props_ui.py b/leenkx/blender/lnx/props_ui.py
index c266d9c..6811a92 100644
--- a/leenkx/blender/lnx/props_ui.py
+++ b/leenkx/blender/lnx/props_ui.py
@@ -205,6 +205,8 @@ class LNX_PT_ParticlesPropsPanel(bpy.types.Panel):
         if obj == None:
             return
 
+        layout.prop(obj.settings, 'lnx_auto_start')
+        layout.prop(obj.settings, 'lnx_is_unique')
         layout.prop(obj.settings, 'lnx_loop')
         layout.prop(obj.settings, 'lnx_count_mult')
 
@@ -240,6 +242,7 @@ class LNX_PT_PhysicsPropsPanel(bpy.types.Panel):
             layout.prop(obj, 'lnx_rb_angular_friction')
             layout.prop(obj, 'lnx_rb_trigger')
             layout.prop(obj, 'lnx_rb_ccd')
+            layout.prop(obj, 'lnx_rb_interpolate')
 
         if obj.soft_body is not None:
             layout.prop(obj, 'lnx_soft_body_margin')
@@ -2730,8 +2733,33 @@ class LeenkxUpdateListInstalledVSButton(bpy.types.Operator):
 
         return {'FINISHED'}
 
+class LNX_PT_PhysicsProps(bpy.types.Panel):
+    bl_label = "Leenkx Props"
+    bl_space_type = "PROPERTIES"
+    bl_region_type = "WINDOW"
+    bl_context = "scene"
+    bl_options = {'DEFAULT_CLOSED'}
+    bl_parent_id = "SCENE_PT_rigid_body_world"
 
-class LNX_PT_BulletDebugDrawingPanel(bpy.types.Panel):
+    @classmethod
+    def poll(cls, context):
+        return context.scene.rigidbody_world is not None
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+        layout.use_property_decorate = False
+        wrd = bpy.data.worlds['Lnx']
+
+        if wrd.lnx_physics_engine != 'Bullet' and wrd.lnx_physics_engine != 'Oimo':
+            row = layout.row()
+            row.alert = True
+            row.label(text="Physics debug drawing is only supported for the Bullet and Oimo physics engines")
+
+        col = layout.column(align=False)
+        col.prop(wrd, "lnx_physics_fixed_step")
+
+class LNX_PT_PhysicsDebugDrawingPanel(bpy.types.Panel):
     bl_label = "Leenkx Debug Drawing"
     bl_space_type = "PROPERTIES"
     bl_region_type = "WINDOW"
@@ -2897,7 +2925,8 @@ __REG_CLASSES = (
     LeenkxUpdateListAndroidEmulatorButton,
     LeenkxUpdateListAndroidEmulatorRunButton,
     LeenkxUpdateListInstalledVSButton,
-    LNX_PT_BulletDebugDrawingPanel,
+    LNX_PT_PhysicsProps,
+    LNX_PT_PhysicsDebugDrawingPanel,
     LNX_OT_AddArmatureRootMotion,
     scene.TLM_PT_Settings,
     scene.TLM_PT_Denoise,