Hey Everyone !

Is it possible to get Geometry attributes in to the RIS networks in Houdini 15 ?
I can get them to work in the RIB side of things but not in the RIS networks
anybody got an idea ?

Thank you so much for your time !


regards

If I read you correctly, you need to use a pxrprimvar node to ingest teh attribute into the shading network.

G

That worked ! I tried Houdini attribs first but they are different for renderman right ? Cs is the surface color instead of Cd right ! Didnt know that !

Is it also possible to have custom attributes in the PxrPrimvar node ?


Thank you so much !


regards

I guess usually you load geometry from file, which means it already contains custom attributes which you can reference in primvar shader.

Otherwise, when you use Houdini geometry straight up, soho needs to write it out to .rib. There is not much documentation, but you can look at buildRixlateList() in RIBsohogeo.py.

It contains a list of attributes that are readily exportable to .rib (ie, Cd, Alpha, N, uv, rest, and pscale). It also hints as how to write out custom attributes. Namely, you will need to add an explicit “rixlate” detail attribute that lists them. It's a string or string array attribute, and value is of the format “AttribClass:HoudiniAttribName:RibAttribName:AttribType:Component”, and you can skip the “Component” part. Check out the attached example.

It turns out there is an easier way of writing out custom geometry attributes to .rib: you can use Attribute Rename ('attribute') SOP, which has the RenderMan tab to specify them.