diff --git a/leenkx/Sources/iron/object/ParticleSystem.hx b/leenkx/Sources/iron/object/ParticleSystem.hx
index 245c525..6e55a36 100644
--- a/leenkx/Sources/iron/object/ParticleSystem.hx
+++ b/leenkx/Sources/iron/object/ParticleSystem.hx
@@ -51,6 +51,7 @@ class ParticleSystem {
 		seed = pref.seed;
 		particles = [];
 		ready = false;
+		
 		Data.getParticle(sceneName, pref.particle, function(b: ParticleData) {
 			data = b;
 			r = data.raw;
@@ -70,7 +71,13 @@ class ParticleSystem {
 			lifetime = r.lifetime / frameRate;
 			animtime = (r.frame_end - r.frame_start) / frameRate;
 			spawnRate = ((r.frame_end - r.frame_start) / r.count) / frameRate;
-			for (i in 0...r.count) particles.push(new Particle(i));
+
+			for (i in 0...r.count) {
+				var particle = new Particle(i);
+				particle.sr = 1 - Math.random() * r.size_random;
+				particles.push(particle);
+			}
+
 			ready = true;
 		});
 	}
@@ -108,7 +115,7 @@ class ParticleSystem {
 		}
 
 		// Animate
-		time += Time.realDelta * speed;
+		time += Time.delta * speed;
 		lap = Std.int(time / animtime);
 		lapTime = time - lap * animtime;
 		count = Std.int(lapTime / spawnRate);
@@ -143,7 +150,7 @@ class ParticleSystem {
 	}
 
 	function setupGeomGpu(object: MeshObject, owner: MeshObject) {
-		var instancedData = new Float32Array(particles.length * 3);
+		var instancedData = new Float32Array(particles.length * 6);
 		var i = 0;
 
 		var normFactor = 1 / 32767; // pa.values are not normalized
@@ -162,6 +169,10 @@ 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
@@ -185,6 +196,10 @@ 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
@@ -195,9 +210,13 @@ 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, 1, Usage.StaticUsage);
+		object.data.geom.setupInstanced(instancedData, 3, Usage.StaticUsage);
 	}
 
 	function fhash(n: Int): Float {
@@ -236,9 +255,10 @@ class ParticleSystem {
 
 class Particle {
 	public var i: Int;
-	public var x = 0.0;
-	public var y = 0.0;
-	public var z = 0.0;
+	public var px = 0.0;
+	public var py = 0.0;
+	public var pz = 0.0;
+	public var sr = 1.0; // Size random
 	public var cameraDistance: Float;
 
 	public function new(i: Int) {
diff --git a/leenkx/blender/lnx/material/make_particle.py b/leenkx/blender/lnx/material/make_particle.py
index a8dd707..d22e534 100644
--- a/leenkx/blender/lnx/material/make_particle.py
+++ b/leenkx/blender/lnx/material/make_particle.py
@@ -86,7 +86,7 @@ def write(vert, particle_info=None, shadowmap=False):
         vert.write('p_fade = sin(min((p_age / 2) * 3.141592, 3.141592));')
 
     if out_index:
-        vert.add_out('float p_index');
+        vert.add_out('float p_index')
         vert.write('p_index = gl_InstanceID;')
 
 def write_tilesheet(vert):
diff --git a/leenkx/blender/lnx/material/make_shader.py b/leenkx/blender/lnx/material/make_shader.py
index 8fd4dda..89f4fe9 100644
--- a/leenkx/blender/lnx/material/make_shader.py
+++ b/leenkx/blender/lnx/material/make_shader.py
@@ -209,7 +209,8 @@ 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'})
-                    if 'Scale' in inst:
+                    #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:
                         global_elems.append({'name': 'iscl', 'data': 'float3'})
 
             elif inst == 'Off':