Sets which method Unity uses to randomly assign Meshes to particles.
The ParticleSystemRenderer uses this to determine how often to randomly select each Mesh.
| UniformRandom | Use a uniform random value to give each Mesh an equal chance to appear. |
| NonUniformRandom | Use per-Mesh weights to make some Meshes appear more often than others. A higher weight value increases the chance of choosing the associated Mesh. |