Set a projector at UVProjection modifier (script)

Question

I am trying to create a script that involves the creation and setup of a UV Project modifier. When it comes to set the UV Map of the projector, there is no problem at all:

import bpy
bpy.data.objects['piece'].select_set(True)
bpy.ops.object.modifier_add(type='UV_PROJECT')
bpy.context.object.modifiers["UVProject"].uv_layer = "UVMap"

But when I'm trying to set the projector object, I find no way to do it, as "projectors" property seems to be read-only:

https://docs.blender.org/api/current/bpy.types.UVProjectModifier.html?highlight=projection%20modifier

Q: Am I missing something or precisely that property is just not scriptable?

Answer 1

Similar to How to add modifiers using python script and set parameters?, the recommended way is to add a new modifier to an object using ObjectModifiers.new() which returns the reference to the modifier and allows to assign whatever you like:

import bpy
Get the object in context
obj = bpy.context.object
Add the modifier to the object in context
modifier = obj.modifiers.new(name="project", type='UV_PROJECT')
Properties
modifier.uv_layer = "UVMap"
modifier.projector_count = 10
for p in modifier.projectors:
    p.object = bpy.context.scene.camera

projectors property is of type bpy_prop_collection, which is essentially a list of object references. In order to assign an object to each Object property of the modifier, you would have to assign an object reference like bpy.context.scene.camera.