Particles with negative scale and a non-Default material does not appear.

Questions & Answers
1

Is there some sort of documentation stating that particles will not appear if they are given a negative scale? I’ve look and didn’t see anything related to this–as well, the Default Particle Material works fine, even when given a negative scale value.

Essentially, the only change I’ve made to the Particle Renderer is to apply my own custom particle material, and the particle system is a child of an object which sometimes will have a negative x scale. When this occurs, the particles will simply not render.

To replicate: Create a new Party System, apply your own material to the Particle Renderer, and give one of the scale values a negative value, and viola, invisible particles!

Any insight would be much appreciate :).

2

Inverting scale would also flip the surface normal; so the particles are most-likely being backface-culled by the renderer.

3

Workaround/Solution: Use the shaders meant for Particle use (namely, under the sub-menu of “Particles”)!