Need a little help unraveling what I'm interpreting wrong as far as what setattrib() is asking for in a VEXpression. I thought I needed to give it the primitive number my attribute wrangle is running through, and the vertex i'm currently on, but @primnum only seems to return the 0 primitive, as can be seen.

Hi,

You can just use this and pass @vtxnum to prim_num and -1 to vertex_num:
https://www.sidefx.com/docs/houdini/vex/functions/setvertexattrib.html [www.sidefx.com]

Hi,

Substitute @primnum with -1, just because @vtxnum is not primitive relative (it is a global value “linear vertex index”).

You can also use “setvertexattrib” directly (to avoid attribclass), or just write @Cd = set(1,0,0);.