object.select_set(True) makes item active, not selected

Question

I'm trying to add a simple triangle to a scene (with Blender demo BMW) using python script. I then want to enter edit mode, select a vertex and then move 3D cursor to that vertex, exit edit mode and then add an area light at the 3D cursor. Repeat to set up very basic three-point lighting. However, when I deselect all objects, and then try to select my "LightingRig" object using the code example, I can see that the triangle is active (not selected, as intended) and I get the following error:

RuntimeError: Operator bpy.ops.object.mode_set.poll() Context missing active object

How can I set the triangle to be selected, and not active?

import bpy
import os
import sys
bpy.ops.wm.append(
    filepath=os.path.join(lr_file_path, inner_path, lr_object_name),
    directory=os.path.join(lr_file_path, inner_path),
    filename=lr_object_name
)
lr = bpy.data.objects.get("LightingRig")
bpy.ops.object.select_all(action='DESELECT')
lr.select_set(state=True)
bpy.ops.object.mode_set(mode="EDIT") # This is where the error occurs

Does this answer your question? Blender 2.8 API, python, set active object Orange color means selected, you want an object to become yellow to be active. — Markus von Broady, May 17 '22 at 14:36
I see. I thought orange was active. However, I'm still getting similar issues.
I'm trying this:

bpy.ops.object.vertex_group_select()

bpy.ops.view3d.snap_cursor_to_selected()

This gives similar context error:

RuntimeError: Operator bpy.ops.view3d.snap_cursor_to_selected.poll() failed, context is incorrect — Chris_S, May 17 '22 at 14:49
This is because there's no 3D cursor inside the Text Editor where you run the script. You need to search for a view3d space to change the 3D cursor there, or do it like here: How to set cursor location, pivot_point in script? — Markus von Broady, May 17 '22 at 14:56
Thanks. I'll take a look at the suggested ideas. First time I've used python and also first time I've done scripting in Blender - there's a lot of quirks :) — Chris_S, May 17 '22 at 18:14
Operators in bpy.ops are for interactive use through the UI and should be avoided in scripts because they depend on context. Using them through scripts may yield unexpected results at best, or fail entirely at worst. Manipulate data directly from bpy.data instead. — Duarte Farrajota Ramos, May 18 '22 at 12:06

object.select_set(True) makes item active, not selected

0 Answers0