MAT vops vs Sop vops

[evanrudefx]

Hello,

I have a few questions about vop nodes in mat context. I have no trouble with vops in sop, but things seem to fall apart in /mat (FYI I am working inside a material builder). 

1. Is it possible to access @ptnum and @primnum? It doesn't seem to work

2. Some binds just don't seem to work. If I do the same bind in /obj vop context, it works perfectly, but binding it in /mat material builder doesn't. Why would it not work in the /mat context when the nodes are the same?

3. If the vop asks for a file and I use op: to get data from a node in /obj, it does not work and says error finding geometry. But if I do the same thing in /obj in a vop network, it works perfectly fine

4. In /obj in a vopnetwork, you can access the input from the geometry vop global parameter node. If the vop node asks for a file, you can wire it into opinput 1. How do you do that in /mat? What if I want to access the geometry to which the shader is applied? It's asking for a file, but I just want to use the geometry to which that shader is applied.

Thanks

[DonRomano]

You can import whatever attribute you want into a material builder by using a bind vop. Make sure to set the right type of the attribute to import (float, integer, vector...). You can also try with a parameter vop with the same name as your attribute to import it. To acces the ptnum/primnum try to use "point.number" and "prim.number", and there's also a node called "Import Surface Variable" which you can give a try.

I'm not sure that you can access geometry from a sop into a material builder, you can access attributes from the geometry that has your shader applied, but not geometry directly (a trick might exist but I don't know it).

Hope that helps,

 

Cheers,

[evanrudefx]

thanks for the tips : )