Collada exporter does not assign any texture when object has multiple UV maps
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Description

System Information
Windows 10, GTX970

Blender Version
Broken: 2.78c

Short description of error
When object has multiple UV maps, Collada exporter does not assign any texture to the materials, even though the texture is displayed correctly in the Blender textured viewport.

Known workaround is to delete all other UV maps, then export works as expected. But then, the object can't be used again to rebake textures when the other UV maps are needed for baking.

Exact steps for others to reproduce the error

  • Object has multiple UV maps and materials
  • Correct UV map (UVmerge) is selected as active
  • Baked texture is assigned to the whole mesh surface in UV Editor (Blender textured viewport displays it correctly)
  • Collada Export with Default SL Static preset
  • Problem: After Collada export, no texture is assigned to the object. Instead, viewport colors are assigned to the materials.

Details

Type
Bug

I decided to try to fix Collada issues myself, but didn't want to recompile C++ code. So, I made a Python based Collada exporter that fixes the issues with UV textures assigning (this one and https://developer.blender.org/T51259). My script uses pycollada module (https://github.com/pycollada/pycollada). I will publish my script after polishing it into an addon.

Finally, I've created my own python based Collada exporter that fixes both issues https://developer.blender.org/T51288 and https://developer.blender.org/T51259

It enables me to export static mesh objects from Blender including all baked textures assigned to the active UV layers, exactly how they are visible in Blender textured viewport. And then, I can upload my build directly to Second Life without the need to apply textures manually, which is a nice time saver. Only drawback is the need for pycollada module that is not a part of official Blender, so must be installed into Blender's folder (eg. Blender/2.78/scripts/modules)

I put my script here: https://github.com/meshlogic/blender-addons/tree/master/collada-exporter-sl