This page provides some details on the settings available for the BSDFPointParticle material node.
Overview
The BSDFPointParticle material is specifically designed for rendering points when the Render Points As (Mantra) option in the Render tab > Geometry sub-tab is set to Circles.
Parameters
Diffuse Color – Specifies the color of the points.
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. See the Effect of the Phase Function Parameter example below.
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.
Notes
- If the material is applied to spherical particles or regular geometry, it renders as a normal diffuse material.