When a ray hits a surface, it can reflect, refract (transmit), or pass through a volume. These are the ray spawn events which we can record with LPE symbols. We use the R symbol for reflection and T for refraction and sub-surface scattering. They can be used directly, e.g. R captures reflections of any scattering type and is also equivalent to <R.>. We can further specify the kind of hit we want to trace by combining R and T with one or more scattering types - diffuse (D), glossy (G), or singular (S). If we don’t specify that, all scattering types are assumed for our R or T events. This allows us to filter the results only from diffuse reflection, for example with <RD> or combine glossy and singular reflection <R[GS]> . By using ray spawn events and scattering types, we can recreate some familiar render elements or create custom single or multiple event expressions. Right click in the expression field to access a list of the available expression symbols and some presets to get you started. |
|