VRay RT GPU (Cuda)

[joss_smith]

Hi,

I noticed there is no V-Ray RT GPU option on the standard install. I added one via Modo's form editor. It *seems* to work.

Is there a reason an RT GPU option is not added in the default V-Ray for Modo menus?

[wolvy]

I was just wondering that. Can you post a screenie of the form editor you used? Thanks!

[joss_smith]

I was just wondering that. Can you post a screenie of the form editor you used? Thanks!

Here are the steps.

[vlado]

Support for Modo's shader tree required us to write several specific shaders for V-Ray; these shaders work for the CPU version but do not yet have a GPU variant. Also, we have not really tested *at all* how the GPU version works in Modo.

Best regards,
Vlado

[vladimir.nedev]

Hi,

I noticed there is no V-Ray RT GPU option on the standard install. I added one via Modo's form editor. It *seems* to work.

Is there a reason an RT GPU option is not added in the default V-Ray for Modo menus?

It is probably falling back to RT CPU. I don't think the RT GPU DLL is installed in the correct location. If you look at the "Event Log"
you will probably see a message like "Failed to load CUDA renderer plugin..."

Getting it to actually work is one of the next major tasks on our todo list.

Greetings,
Vladimir Nedev

[wolvy]

Yeah, it looked promising for a few seconds and thank you Joss, for the screens.

[joss_smith]

Thanks for the feedback. I figured there would be a reason GPU wasn't presented in the standard UI but wasn't sure how to phrase the question.

Support for Modo's shader tree required us to write several specific shaders for V-Ray; these shaders work for the CPU version but do not yet have a GPU variant. Also, we have not really tested *at all* how the GPU version works in Modo.

Best regards,
Vlado

I like the "yet". Promising!

It is probably falling back to RT CPU. I don't think the RT GPU DLL is installed in the correct location. If you look at the "Event Log"
you will probably see a message like "Failed to load CUDA renderer plugin..."

Getting it to actually work is one of the next major tasks on our todo list.

Greetings,
Vladimir Nedev

More good news Honestly I was beginning to doubt I'd achieved anything because the performance was pretty much identical to CPU Compute. Lo and behold the logs do reveal that fallback occurred so it was CPU compute after all.

Very glad to hear that GPU compute is coming.

[Robotti3000]

My four 750ti's are also looking forward to some serious render work!

[vladimir.nedev]

The latest nightly builds have a "Start RT GPU CUDA" option in the V-Ray menu and toolbar. It will no longer fall-back to RT CPU.
It is still a very early version though. MODO's advanced material is exported in a very different way compared to the RT CPU version.
The results will not be as close as in the CPU version. Generally it is best to use RT GPU with the V-Ray material.

Also none of the special textures, that we wrote for supporting MODO's shader tree and textures, are implemented on the GPU yet.
Some stuff that works in the CPU version, but won't work in the GPU version:
- gradient texture
- environment material ( you can still use a texture for the environment though)
- blending of texture layers in the shader tree
- stencil texture effect
- possibly other things as well

There is also an intermittent crash when changing material properties.

You can hopefully run some tests on it.

Greetings,
Vladimir Nedev

[tim_harding]

I'll test this when I get home. I hope there will be a simple, obvious method for setting up final frame animations on the GPU. It's something that took me a little while to figure out in the Maya version, but a feature I suspect loads of people will be using soon. I'd also mention the gradient texture would easily be the most important thing to integrate in the next version. I use it on virtually every map when making materials.

[vladimir.nedev]

I'll test this when I get home. I hope there will be a simple, obvious method for setting up final frame animations on the GPU. It's something that took me a little while to figure out in the Maya version, but a feature I suspect loads of people will be using soon. I'd also mention the gradient texture would easily be the most important thing to integrate in the next version. I use it on virtually every map when making materials.

There isn't a way to render an animation at the moment. I have to look how V-Ray for Maya does it, and see if it can be made easier.
What inputs of the gradient texture are the most important - incidence angle maybe ?

Greetings,
Vladimir Nedev

[tim_harding]

I would say incidence and driver A. I usually will set my greyscale maps (gloss, reflection amount, bump) to driver A and then pipe them through a gradient set to the proper effect so I can tone them. I can make pretty decent shaders this way using one or two bitmaps, because you can have one image file driving various gradients for different material parameters.

[Dentzz]

Any update on Vray for Modo using GPU, also any chance it will be in the next public beta release?

[vladimir.nedev]

Any update on Vray for Modo using GPU, also any chance it will be in the next public beta release?

I haven't had the time to implement any MODO specifics on the GPU so far. You can run RT GPU CUDA in the latest (3.00.05) public beta release.
Just execute the command "vray.render false rt-gpu-cuda start". I've hidden the command from the interface, because there are very frequent crashes when you change material
properties. Those crashes are fixed for 3.00.06.

Greetings,
Vladimir Nedev

[vladimir.nedev]

I would say incidence and driver A. I usually will set my greyscale maps (gloss, reflection amount, bump) to driver A and then pipe them through a gradient set to the proper effect so I can tone them. I can make pretty decent shaders this way using one or two bitmaps, because you can have one image file driving various gradients for different material parameters.

This has been working in RT GPU in the nightly builds for some time now. Also, it will be part of the coming 3.01.02 official beta build.
It won't work on the bump slot though, there you can have only an image map texture.

Greetings,
Vladimir Nedev