GPUParticles3D
Alpha Over Time:
Make sure that in the material for geometry instance, check the box for Vertex Color > Use as Albedo
You can use Alpha Scissor Transparency mode to do an erosion effect with this
Scale Over Time:
If using billboards in 3D, the scale of the mesh is lost by default. You must enable "Keep Scale" in the Billboard options of the material to use the scale from the particle system.
