Photon RTXPT
Materials
Principled, emission, and glass materials — bound by path, driven by TOPs.
A Photon Material binds a look to geometry by path pattern. Any channel can be a constant or a TOP — textures stay on the GPU end to end.
Material models
The workhorse — a Disney-style BSDF matching what your offline renderer calls Standard Surface.
| Channel | Takes | Default |
|---|---|---|
| Base Color | RGB / TOP | 0.8 gray |
| Roughness | float / TOP | 0.5 |
| Metallic | float / TOP | 0 |
| Normal | TOP | — |
Glass needs path depth: at the default 4 bounces a glass-in-front-of-glass
shot goes black where paths run out. Raise Max Bounces to 6–8 for
transmissive scenes and watch the ms/frame readout.
Binding
# Bind by path pattern, most-specific pattern wins
op('photon_mat_floor').par.bindpaths = '*/floor_geo'
op('photon_mat_hero').par.bindpaths = '*/hero/*'Unbound geometry gets the default gray Principled — a scene never fails to render because a pattern missed.
Wildcards make LOD swaps free: bind */statue_* once and every resolution
variant inherits the same look.