# Copying Group Instance Computation Expense

I am pushing into the scene around 38k to 50k cube instances using Python, however, I am reasonably expecting to finish the execution of the code within ten minutes or so, I am OK with an hour at most. But it's taking 11h to finish.

Here the code where I placing the cube Instances

for l in localizations:
i = 0
buffer = []
gens = random.randint(6, 16)
probability = np.random.uniform(.1, .8, 1)
status = initial_status(gens, probability)

while np.all((status) == 0) == False:
status = make(status)
buffer.append(status)

if len(buffer) > 5:
buffer.pop(0)

for j in range(len(status[0])):
for k in range(len(status[1])):

if status[j, k] == True and len(bpy.context.scene.objects) == 1:
location=(l[0]+j, l[1]+k, i),
scale=(1, 1, 1))
mat = bpy.data.materials.get("Material")
mat1 = bpy.data.materials.get("Material.001")

for ob in bpy.context.scene.objects:
if ob.name.startswith("Cube"):
ob.data.materials.append(mat)
if ob.name.startswith("Plane"):
ob.data.materials.append(mat1)

bpy.ops.collection.create(name="cubes")

if status[j, k] == True and len(bpy.context.scene.objects) > 1:
location=(l[0]+j, l[1]+k, i),
scale=(1, 1, 1))
i+=1


Whether I push mesh.primitive or instance it gets slower exponentially. I couldn't understand this, to be honest.

in the function call 'make' has 2 * np.where, one multiply op. and one sum op. of two arrays. That mean, basically has no mentionable effect on computational cost. In addition all the arrays dims that two nested loop checking element by element are max 16x16, which also as small as not even mention it. One more extra question is: In the "Current file" section in Blender's right panel, there is let say 40k object in objects folder seperately, and also in scene sections; scene collection and object section has 40k element both. Totally there shows 120k but three copy of same elements. Does this make sense?

• Calling multiple operators per loop how many times? see Issues related to blender.stackexchange.com/questions/163796/… (particularly part re using operators in a loop Possible dupe) Consider dupliverts blender.stackexchange.com/questions/163796/… or blender.stackexchange.com/a/61254/15543 for making an array (eg make mesh array and dupli) if result is array. Mar 1, 2021 at 13:07
• like I've said; one 'multiply operation' per loop. basically I automated this operation: link, In the code I've just using bpy.ops.mesh.primitive_cube_add one times if the all scene has only one object that is the plane itself, I am adding it from out of the loop. rest of the cubes are just copied version of the collection. Mar 1, 2021 at 13:57
• To reiterate calling operators many times is going to be slow. How many operators are you calling altogether? Hard to know given no idea re the unknown variables used but not defined in question code. bpy.ops.object.collection_instance_add is also an operator (and is unrequired can all be done via API methods) Mar 1, 2021 at 14:12
• I am just calling bpy.ops.object.collection_instance_add approx 30k to 50k times, because that much of cubes I need in the scene. rest of the code do not have any effect on the computation as I mentioned it. The make function has just one summation and one multiplication and 2 np.where, which is condition. When you run np.dot(arr(16x16), arr(16x16)) million times it takes 1 sec or so. so no effect. if you must know len(localization) is around 60, while loop continues until all the arrays elements converges to 0, and pushes the cubes at the location where arrays element is grater than 0. Mar 1, 2021 at 14:52
• yep! now I can push 10k in 6 sec so, it is working. Mar 1, 2021 at 15:27