[HOU-2475] Does VRayViewportTex SOP works? How do you preview teextures applied to your VRay materials?

[pablo_rohtau]

Hello.
Sorry for the noob question, but how do you guys preview the textures you use in your vray materials in the viewport?
Read about VrayViewportTex SOP but couldn't it to work.
Any suggestions?

Thanks

[chakarov]

What Houdini version and V-Ray you are using ? Seems that in 18.5 it is not really needed anymore.

[pablo_rohtau]

Hey chakarov.
We are using H18.5.408 and Vray 5.00.50 on windows.

[chakarov]

OK, sorry my bad. ViewportTex is needed to show uv transforms applied via ImageFile VOP. So you need just to add it at SOP level and it will find material/s if they are set via Material SOP.
ViewportTex only work with V-Ray Material Builder or V-Ray Material Builder Complex.
Be sure the texture you want to see is selected in Material Builder "Viewport Shading" tab.
ViewportTex help page
check the example

[pablo_rohtau]

Thanks for the example chakarov.
I got an error.

Also as part of my original question, hoe people get a more or less decent preview of the VrayMaterial in the Opengl Houdini viewport?

[Gosho.Genchev]

Hey Pablo,

There's an option on the V-Ray Material VOP to specify a texture to show in the viewport. It relies on the regular OGL parameters that Houdini uses. As Georgy mentioned above, one of the drawbacks is that the UV mapping is not handled so the preview is quite limited. We could hook up the OGL parameters that look up the mapping and link them to the Image File VOP that's loading the textures but then there's always the possibility that there's a "uvwgen" input node in the Image File VOP ... and then it gets messy.
Regardless, I suppose we could at least do the base case and hook up the OGL UV options. I'll log it and message back.

Best regards!

[pablo_rohtau]

Ja found it! I was looking in the VrayMaterial and it is in the Material Output and then promoted to the Material Builder.
For preview is good enough, I wonder if it is worth for you guys to have your own glsl shader that reis to mimic the VrayMaterial as mush as posible?
I know Houdini is quite limited in it's viewport preview, but looking into tyhe future, in USD, the Hydra delegate is way better in terms of previewing opengl.
Thanks!