i’ve tried to use the Displacement feature of a Physically based material on a mesh plane with 100x100 faces. Once i assign a texture, it doesn’t show any displacement at first. Below changes to the material do not seem to update but trigger a re-render in the Raytraced viewport:
Changing height
Change texture
Change texture repeat values
Turn slot Off / On
The only way to update the displacement seems to turn Raytraced Off and then back on. Sometimes it updates if i set a low sample count and wait until it is finished but this only works 1/10 times at least.
Why does it re-render when i have e.g. a texture in the slot (light bulb OFF) and change the texture file or height of the displacement ? Imho it should not do that. It should notice that the change made to the parameter will have zero effect because the slot is OFF.
Changing PBR displacement indeed doesn’t reflect in an active Raytraced view, this has been the case already since Rhino 7. RhinoCycles does not have the original mesh which would be needed. When a material is changed only the material changes are being given to RhinoCycles. Not holding on to the original mesh is done on purpose, since these can be very large to get any displacement visible (dense geometry is needed for PBR displacement).
RH-62873 Raytraced does not react to displacement changes while active
Rhino is essentially restarting Raytraced, not Raytraced itself. RH-86898 Don’t trigger Raytraced restart on unimpactful changes
thank you @nathanletwory for adding it to the bugtracker. I’ve asumed that above changes are part of the material since i can see it update eg. for diffuse, bump etc. (btw. first link seems to non public).