[Blender Bug] Render crash, incorrect renders when rendering geometry attributes

[rlguy]

Geometry attributes were a feature introduced in Blender 2.93 Python API. This feature allows for the FLIP Fluids addon to attach custom data to the fluid surface mesh which can then be accessed in Cycles (Velocity based shading animation example).

There is currently a bug in Blender which can cause random crashes or incorrect results during render when rendering surface and whitewater attributes. This bug has been reported here:

June 3rd 2021, T88811: Render crash when using Python API to modify object Attribute data in frame_change_pre handler

At the moment, the only known workaround is to render from the command line.

When this issue is fixed, we can begin moving attribute based shading features into stable versions of the FLIP Fluids addon as well as focus more on expanding these features. This includes features such as:

• Velocity or speed based shading
• Fluid age or remaining lifetime based shading
• Basic coloring based on fluid emission source (multiple liquid coloring)