Closed portsmouth closed 2 months ago
OK yup, just a misunderstanding on my part. Indeed, a rough coat should roughen the transmission lobe. This needs to be mentioned as part of https://github.com/AcademySoftwareFoundation/OpenPBR/pull/172, i.e. exactly what in the model is modified by the coat roughening effect.
Actually, no, it does make sense. The transmission_roughness
in this can be replaced with main_roughness
:
<dielectric_bsdf name="dielectric_transmission" type="BSDF">
<input name="weight" type="float" value="1.0" />
<input name="tint" type="color3" nodename="if_transmission_tint" />
<input name="ior" type="float" nodename="modulated_eta_s" />
<input name="roughness" type="vector2" nodename="transmission_roughness" />
<input name="normal" type="vector3" interfacename="geometry_normal" />
<input name="tangent" type="vector3" nodename="main_tangent" />
<input name="distribution" type="string" value="ggx" />
<input name="scatter_mode" type="string" value="T" />
</dielectric_bsdf>
As there is no need to distinguish between the "transmission roughness" and the "reflection roughness" of the dielectric (in OpenPBR).
We do still need to clarify the implementation in https://github.com/AcademySoftwareFoundation/OpenPBR/pull/172.
Isn't the
transmission_roughness
value still referenced in thedielectric_transmission
node of the graph?https://github.com/AcademySoftwareFoundation/OpenPBR/blob/main/reference/open_pbr_surface.mtlx#L412