This page provides information on the Point Particle Material.
The VRayPointParticleMtl material is specifically designed for rendering particles coming from Alembic or .vrmesh files when the particle render mode in the VRayProxy object is set to Point.
Diffuse color – Specifies the color of the particles.
Diffuse map – A texture map that can be used instead of the Diffuse color.
Use particle color – When enabled, the material attempts to take the color from the native particle color channel in the Alembic file, if such a channel is present.
Phase function – Specifies how light scatters from the point particles. A value of 0.0 means perfect diffuse scattering in all directions. Values close to 1.0 specify that light scatters predominantly in the direction that it comes from. A value close to -1.0 specifies that light scatters mostly backward. The phase function is useful to simulate scattering from water mist or steam, in which case values between 0.0 and 1.0 work best. For dust particles, smoke, or soot, a value of 0.0 is more appropriate. The particular phase function model that is implemented is the Henyey-Greenstein model.
Example: The Effect of the Phase Function Parameter
In the images below, we have particles randomly distributed in a plane, with two spherical lights behind and in front of the plane. The images show how the particles scatter the light coming from the spherical lights depending on the Phase function parameter.
The Phase function is 0.0 and the particles scatter light uniformly.
This is characteristic for particles that form dust, smoke or soot.
The Phase function is 0.8 and the particles scatter light predominantly forward.
This is characteristic for the way light is scattered from water droplets.
The Phase function is -0.8 and the particles scatter light backward.
- If the material is applied to spherical particles or regular geometry, it will render as a normal diffuse material.