Real advantages of USD support?

[Karol.Osinski]

Hi all,
Have any of you guys tried the USD workflow? I have never used the USD files but from what I understood it is type of file that Maya can process very fast, and more importantly it is editable directly from the scene, am I correct?

For bigger scene we usually try to use PROXIES and Maya References but I find that editing references, even moving an object can cause a lot of troubles to the point when it makes the heavy Maya scene almost unusable.

Are USDs a holy grail when working with big scenes? I am talking about ones that takes up to 120GB of RAM to render.

Since the V-Ray USD support is new, did you any main issues with it?

regards,
Karol

[Karol.Osinski]

For example, would you choose to turn a 10million poly tree into V-Ray proxy or USD ?

[stezza]

As I understand it you wouldn't want to use USD to replace a proxy tree unless you wanted to edit the tree to have a different look. A USD animated character could have many different clothes and props which can be swapped out even all the way down to texture placement. I still use scene assembly and dont really feel the need to use USD especially for a single user.
For massive scenes I always use a combination of Scene assembly, I can swap out a proxy for the Maya scene file or low res version to bounding box. At render time you just set the Scene assembly render settings to Custom then set your Representation label (In my case I label every asset to "proxy") This loads up the proxies at render time.

[Karol.Osinski]

Hi stezza, thanks for your reply. I am in Archviz field and I am looking to optimize our scene for the best performance / cooperation possiblites.
I am slowly getting into Scene Assembly, so far I love the viewport performance of GPU Cache , although I am not able to get it working with VRay Proxy, the moment I choose .abc file to represent Proxy in the viewport, I lose all the proxies instances.

[stezza]

Hi there, you need to set the path to the Maya scene file which holds the proxy. So when you creat your scene definition you can link in the saved Maya scene file, along with gpu cache, bounding box or any variant you need.

[Karol.Osinski]

So...
1. I have a single TreeProxy.mb file with a single PROXY tree in it.
2. I create a new scene with a scene assembly node and as a Scene Representation I use that TreeProxy.mb file
3. For the Cache Representation I created an .abc file using original high res model of that tree.
4. So far so good.
5. From this point, how should I approach instancing that proxy?
a) instancing the proxy node causes it to break something because it looses that green indicator in the outliner, furthermore when I switch to representation to GPU Cache, it breakes the connection even more and leaves me with GPU preview of just original tree
b) In order to maintain the proxy instances I instanced them directly inside original TreeProxy.mb file and once loaded as Scene Representation the show up as nodes with green indication, although switching to GPU Cache Representation leaves me again with only the one original node

I hope I didn't make it too confusing. Would you please point me out how should I approach it?

regards,
Karol

[stezza]

1. When you make your TreeProxy.mb, make sure you have "Automatically create proxies" at the bottom of the Create V-Ray Proxy panel.
This will create the proxy within the scene with all textures connected and use this scene file to be part of your assembly definition node.
2. If you want to duplicate that tree once it is part of the assembly reference node you need to make sure you use "Duplicate Special options turn on Duplicate input graph.

[stezza]

Proxy tree in assembly definition duplicated.
For lots of trees use MASH with your proxy file to create forests.

[Karol.Osinski]

Thank you so much stezza , I was fine with initial proxy creation. What I was missing was that I never created an assembly reference like you do.
All the proxies are working properly now, also the "proxy" label does the trick at render time although objects aren't rendering during the IPR which is a big no no for me us :/ (I think someone has already mentioned that on the forum).

I love the viewport peformance, being able to have hundreds of high res trees in the viewport, but I still didn't figure out how to switch them all at once between Cached GPU / Proxy preview.

Another pretty big problem is that when I start render, every single of .mb file containing proxy has to load first...in case with hundreds of instances it takes a good while. Does it happen to you too?

Thanks a lot again.

[stezza]

The image I posted was IPR!!
To change them all to gpu cache just select them all in the outliner and right click go to scene assembly> cache..

It does work.