OpenUSD and Vray

[sharktacos]

Pixar has released USD (Universal Scene Description) as open source. I'm wondering if it will work with Vray or if there are plans to make it do so?

From what I can see, the Pixar Github page has an uncompiled version of the Maya plugin which does not currently work on Windows OS. Anyone know of a compiled Windows plugin for Maya? I see that Foundry Katana is planning on writing one, and that Multiverse has one available in beta.

Is anyone using USD currently in production? What are the advantages/disadvantages of USD, as compared to an Alembic pipeline?

This realtime graphics from Hyrda (which comes with USD) looks pretty amazing, when compared with Maya's Viewport 2.0:

[mitchell_architecural]

I'm curious about this as well. I haven't read anything regarding Vray and Universal Scene Description.

[joconnell]

The default USD is better written as far as I know, the isotropix guys did a demo of the same asset as usd and alembic with the only difference being the load libraries for each - usd played back something like 42 times quicker in the viewports? Alembic has a tonne of dumb code that can be heavily streamlined too, one of the guys in here has recompiled exocortex crate with some of those fixes and gotten massive jumps in performance. It'll never leave the company though unfortunately :/

[yolov]

We're still considering what the best approach would be, but we've not made direct support for the moment. If the DCC app handles the USD data (like Katana would do) then this data is passed to V-Ray and it will work.

[LL_Will_J]

Hi Alex,

Seems like a lot of tools (Katana, Houdini, Clarisse and the maya implementation in the works) are embracing OpenUSD (Not to mention Renderman and Arnold working hard on deep integration).

I would be interested to know what Chaos group's current (2019) thinking on USD is? It does look like a very elegant way of working for larger productions.

I would also be interested to know if there are thoughts on supporting other open source tools from the VFX industry like MaterialX?

Many thanks!

Will

[yolov]

I can't share any info at the moment on progress or time-frames. But we want to make sure we have all the info we need to make the best decision (and a useful implementation).
With that said - yes, we are considering an implementation, but there's still a lot of unknowns.
For example:
1. if the host application took care of USD information, then V-Ray will just translate it - is that enough?
2. do you need to render USD files with V-Ray outside the host application (i.e. with V-Ray Standalone)?
2.1. If yes (to USD-V-Ray integration) - what's the use-case? You would swap USD files or version them and render with standalone? Is there another use case?
3. If both the host application and V-Ray had their own (separate) implementations - which one would you use?
3.1. That's the case with alembic files at the moment - you can load them with Maya or with VRay (with a vrayProxy)
4. How would material assignment happen? Will you expect USD to caryy information on what material assignments are expected or would you overwrite those once the file is imported?
5. How would light-linking happen?

Feel free to share more thoughts, as I've probably missed something important.

[sharktacos]

4. How would material assignment happen? Will you expect USD to caryy information on what material assignments are expected or would you overwrite those once the file is imported?

Either material assignments would be exported as part of USD (which is what they currently have for Renderman), or alternately they would be exported separately with MaterialX (which I understand is working together with USD).

[colorbleed]

Hi Yolov, just wanted to also note our interest in USD with V-Ray. I've tried to shed some light on most of your questions below.


1. if the host application took care of USD information, then V-Ray will just translate it - is that enough?

With maya-usd being open-sourced and seeing a lot of activity the goal is to have that as the "go to" default. Plus, it's seeing support from Autodesk, Pixar and Animal Logic where there previous separate endeavors of developing maya plug-ins is to be merged into a single plug-in.

Our (Colorbleed) end goal would be to use USD throughout our pipeline and allow rendering of the scenes without requiring to load all data natively into Maya but instead just load the usdProxy shapes and manage things through that. This would allow scenes of much higher complexity to be defer loaded, work in the USD format and get passed on optimally to the renderer. Also see: https://github.com/Autodesk/maya-usd/issues/38

Additionally with the viewport delegates for those USD proxy shapes it would be the ultimate new proxy format that can also be managed into detail - quite the end goal!

2. do you need to render USD files with V-Ray outside the host application (i.e. with V-Ray Standalone)?

I believe that would be part of the process yes, where the renderer would be capable of understanding how to translate the USD content manually so that the optimal loading is focused in that area without requiring too much effort on the Maya front.

2.1. If yes (to USD-V-Ray integration) - what's the use-case? You would swap USD files or version them and render with standalone? Is there another use case?

In our case it would often still be a submission to the renderer from the Maya scene and we would do little to no solo V-Ray standalone work. So I guess I can't answer this.

3. If both the host application and V-Ray had their own (separate) implementations - which one would you use?

At this stage I'd use the maya-usd proxy shapes, and hopefully also have multiple renderers understand how to render those as opposed to each their own proxies.

3.1. That's the case with alembic files at the moment - you can load them with Maya or with VRay (with a vrayProxy)

It's definitely about understanding the usdProxy shapes. Potentially with a custom "set" you can add them to or custom attributes (or a custom manager) for local scene USD overrides that would be specific to V-Ray. But again, I think the focus from V-Ray should be on being able to render the USD content and (where possible) help in the development of maya-usd to allow managing shader assignments, etc.

4. How would material assignment happen? Will you expect USD to caryy information on what material assignments are expected or would you overwrite those once the file is imported?

Potentially through materialx or some type of assignment in the USD data. Unfortunately I know to little about this topic at this stage, but continuing the discussion in this issue could maybe shed some light on it from the community: https://github.com/Autodesk/maya-usd/issues/38

5. How would light-linking happen?

Potentially with custom metadata in the USD scene once it's possible to use the USD tools via maya-usd to add that information as USD edits into the usd files.