[HOU-1906] Proxy Texture Mapping GPU

[Ashcic]

Hello,

I've made a proxy from a geometry that has UVs and a material. On import the proxy is only geometry, which I'm expecting. The problem is that I cannot add UVs to the proxy in Houdini in order to correctly add the material to it again.

I've tried adding UV Texture Mapping in the material, which works for CPU, but not for GPU.

Am I missing something?


Ash

[psanitra]

Vray Proxy stores UVs, but when you load the exported vray proxy back, you need to assign you material again.

If you want to import geo+material together, you can use vrscene for that. Just create vray rop, force only that single object to render, with no lights and set the rop to EXPORT mode. That will save the object to vrscene, including materials. Then just import back with vrscene node.

[chakarov]

Hello Ashcic , V-Ray proxy is a "ready to render" format which does not allow modification in it's content, that's why adding a UVs after import not working. If you want to modify the content of a proxy you should first toggle "Expand primitives" in "Main" tab and switch "Preview type" to "Full Geometry" and unpack SOP after, this will bring the actual geometry into the scene as a mesh. I just find an issue where uvs are not expanded after unpacking the proxy. But uv transformation in materials are working on CPU and GPU. Can you be more specific about your OS, Houdini and V-Ray build so I can test it here, or send me a scene where uv transformation in material are not working in GPU.

[Ashcic]

Hello,

Thanks for that feedback! It's good to know. psanitra I think for some projects, you're right the vrscene is definitely the way to go.

chakarov I've used unpacked primitives before, but I didn't change the type to Preview, that's also a really helpful piece of advice.


Sorry for not being clearer before. I model a lot of things in Rhino, and I've been saving them as Vray proxies and bringing them into Houdini to animate. Usually UVs don't matter because the parts are glass, metal, plastic etc.

However, recently I've had a motion design project where I need to vary the material in Houdini. It's very simple at the moment, just some basic pipes with a material that goes from a transparent glass to opaque plastic. I modelled them in Rhino, added planar UVs and a material, everything works fine in Vray for Rhino.

Now on bringing them into Houdini via proxy import, I built a simple gradient material that goes from Black-Red-White. When I add it to the proxy, It's just black.

Then I added a Texture Mapping node with Planar projection, and I get some colour variation, which renders differently from CPU to GPU. Neither of them look as I had hoped, and there seems to be nothing that I can do to change the mapping.

To solve this would be a massive help in my workflow.


Ash


P.s the photos here are of the material that I was trying to apply, the GPU version of the rendering and the CPU version of the rending.

[chakarov]

Can you also upload an render from Rhino so I can see what you are trying to achieve.

[Ashcic]

Sure, here's a rough view

[chakarov]

Ashcic , could you send me rhino file so me and colleagues from V-Ray for Rhino team check your Rhino setup and find a way to reproduce it in Houdini? Here or at georgy.chakarov@chaosgroup.com.

[chakarov]

Hello again Ashcic , with the help of my colleagues from V-Ray for Rhino team we found why proxy is mapped wrongly when rendered in Houdini. Rhino uses uv indexes for mapping channels, so you need to use "V-Ray UV Channel Index" in Houdini with channel index 1. Otherwise uvs of the vrmesh can't be handled.

[Ashcic]

Thanks Georgy!

It worked like a charm. I used the UV Channel index to set the UVs in the material, and it came out perfectly.

https://docs.chaosgroup.com/display/...+Channel+Index