How to add a new UV map to all selected objects?

Question

I would like to select multiple objects and add a custom UV set to all of them. My version works for one selected object only but not for multiple selected objects.

import bpy

# Get all selected objects
selected_objects = bpy.context.selected_objects 

for obj in selected_objects:
    # Add new UV set
    bpy.ops.mesh.uv_texture_add() 
    # Set new UV set name for active UV set
    bpy.context.object.data.uv_layers.active.name = "UV_ao"

What's wrong with my code?

You need to set the active object during the for loop. bpy.context.view_layer.objects.active = obj — Ratt, May 04 '20 at 09:11
Thank you a lot for the fast answer. All works fine! I've added the right code below to help others. — Christoph Werner, May 04 '20 at 09:14

score 4 · Answer 1 · edited May 04 '20 at 15:35

4

You can get rid of the uv_texture_add() operator by adding a new UVLoopLayer:

import bpy

for obj in bpy.context.selected_objects:
    # Make sure this is a mesh object and that it doesn't already use this UV Map
    if obj.type == 'MESH' and "UV_ao" not in obj.data.uv_layers:
        obj.data.uv_layers.new(name="UV_ao")

edited May 04 '20 at 15:35

brockmann

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answered May 04 '20 at 09:53

Gorgious

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Thank you for this hint! – Christoph Werner May 05 '20 at 10:13
@brockmann Thanks for the edit, would you care to explain why the single quote around 'Mesh'but not around the other string ? – Gorgious May 05 '20 at 11:08
2

Readability. "Use single quotes for enums, and double quotes for strings.", quote from: https://docs.blender.org/api/current/info_best_practice.html – brockmann May 05 '20 at 11:10
@brockmann Oh, right. Thanks ! – Gorgious May 05 '20 at 12:13

score 2 · Accepted Answer · edited May 05 '20 at 10:30

2

In order to make the operator work for multiple objects, the current object in the loop needs to be assigned to ViewLayer.active before calling uv_texture_add():

import bpy

# Do the following for all selected objects
for obj in bpy.context.selected_objects: 
    # Set current object in the selection as active
    bpy.context.view_layer.objects.active = obj 
    # Add new UV set to active object
    bpy.ops.mesh.uv_texture_add() 
    # Set the name of the uv layer
    obj.data.uv_layers.active.name = "UV_ao"

Related: Blender 2.8 API, python, set active object

Another way is overriding the context of the operator by passing the object:

import bpy

# Do the following for all selected objects
for obj in bpy.context.selected_objects:
    # Override the context by passing the current object
    bpy.ops.mesh.uv_texture_add({'object': obj})
    # Set the name of the uv layer
    obj.data.uv_layers.active.name = "UV_ao"

edited May 05 '20 at 10:30

brockmann

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93

answered May 04 '20 at 09:16

Christoph Werner

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1

Why are you assigning "UV_ao" string to the the active UV-layer of the object in context when looping through the objects anyway? Btw: you don't have to assign the object to the ViewLayer.active. You can override the context by passing the actual object {'object': obj} to uv_texture_add() operator, call is: bpy.ops.mesh.uv_texture_add({'object': obj}). – brockmann May 04 '20 at 14:51
Sorry guys. I forgot to delete the last line, because of using it in my scene here. my objects have all a minimum of one UV set. But thank you a lot for the forther information, That helps! – Christoph Werner May 05 '20 at 10:09
1

No need to say sorry. Just read the comments again and try to understand them. – brockmann May 05 '20 at 10:14

How to add a new UV map to all selected objects?

2 Answers2