UV Map random swap - with multiple materials and UV Maps
Open, Needs TriagePublic

Description

System Information
Windows 7 64-bit
GeForce GTX 680

Blender Version
Broken: 2.78c official release
Worked: 2.78a official release

Short description of error
When an object has more than 1 material and more than 1 UV Map (each material using a different UV Map in the material nodes), occasionally a material will use the incorrect UV Map during animation. On average, it happens around 4-8 times per 100 frames.

Very rarely it might crash.

I could not reproduce this with only 1 material and multiple UV Maps.

Exact steps for others to reproduce the error
The attached file has 1 object with 2 materials, each using a different UV Map.

  1. open file and Render Animation
  2. check animation result

If same problem occurs, a dot will move occasionally (uses different UV map) on a few frames.

Details

Type
Bug

In my testing, the problem doesn't occur in the following situations:

  1. 'Open Shading Language' enabled

Which is not very helpful when depending on GPU rendering

  1. 'Persistent Images' enabled

Not sure yet how this would affect more complex animation