create USD variants in maya 2022

[ignaciogasco]

Hello,

I was wondering if there is a way to create USD variants in maya 2022. I am able to read variants  perfectly but I'm struggling to create them.

Thank you very much

[Anonymous]

I was also struggling about that. It seems Maya usd doesn't support the variant editor yet. Though it's a must for the usd workflow.

Hopefully that will change for the next update.

For the moment I use Houdini when setting variants. 

[Anonymous]

Two years. One release skipped. You're saying it's fully integrated while its barely integrated. It's just sad and pathetic at this point. Shame on you Autodesk. 
Nice to meet you Houdini ❤️

[will.telford]

Currently Maya USD allows for setting variant sets to a variant through the right-click menu in the Outliner in Maya 2022+.

It does not yet have a variant editor for creating variantSets, variants, or targeting edits to variants.

A user can still do it in the Maya script editor using the Pixar USD Python API as you have full script access to the USD stage. Pixar provides a tutorial on how to do this here:

https://graphics.pixar.com/usd/docs/Authoring-Variants.html 

The Maya USD plugin is maintained as an open source project and the following link is the best place to get your questions answered (As well as grab the most current version of the plugin).
https://github.com/Autodesk/maya-usd/discussions 

[will.telford]

Its worth mentioning that there is already a conversation in progress on a similar topic on the plugin's GitHub discussion forum here.

https://github.com/Autodesk/maya-usd/discussions/1054#discussioncomment-641407 

There are two approaches to solve here. The one in the discussion linked is about how to tag Maya data so that it exports to USD as varaints.

The other issue at hand is how to author variants directly to USD in memory when working with a stage.

[chris.browneBYWDP]

Are there any updates here?
1. Can we author usd variants yet in maya?

2. Can we export that data within the usd to be used in unreal?

[susej2042]

I don't think there's nothing yet at this time

[Christoph_Schaedl]

We use Bifost for variants.
https://youtu.be/icZA6oZ2ozs

[cbrowneL7QTD]

this is cool but you have to save off the variant as a stage in this technique. However if you look at the kitchens set, the variant usds are not individual stages. Any solutions?

[Christoph_Schaedl]

A stage is just a file on disk like the assets in the kitchen set. You can compose those new stages in a single file in the end. Thats the power of USD you layer together what you need and all data is on disk to be consumed by different Artists and departments.

Take a look a more modern USD Scene like the AnimalLogic Lab.

https://animallogic.com/alab/

[Christoph_Schaedl]

On the Bifrost Discord are some sample scenes on how to create Assets with Variants.

[cbrowneL7QTD]

if you look at the kitchen set, they have props that have variants (usd's) BUT not stages.

I'd like a usda with variants but that is not a stage like in the kitchen set.

[Christoph_Schaedl]

Thats only possible cause all variants are parts of the kitchen usd. In this case build the whole scene in Bifrost with variants.

But this isnt the workflow USD is made for. You cant work with multiple artists in parallel this way.

[cbrowneL7QTD]

Thank you for your replies! On a Saturday no less 🙂

Ok so I guess I have a workflow question.

If I want to build an environment with lots of props that have variants, for example a Rock (variants are "stone", "boulder", "pebble").

A layer in the stage is "Forest". Do I bring in the rock as a sublayer under the forest layer? SO I am not bringing it in as a Xform/Def/Ref of a usd? But rather a sublayer in the USD Stage?

[Christoph_Schaedl]

Thats up to you. There are no golden rules for USD. Some use the layers to seperate the departments in the studio. Some use them to organize the scene.

[cbrowneL7QTD]

but it seems weird to have a prop of a rock as a sublayer... so basically any time you have a prop that has a variant has to be a 'sublayer'?

this is going the bifrost route. the only way to save the variant is as a stage. Which means it can only be brought in as a sublayer and not as a usdc reference under a 'def'. 

I do not see any other way with maya for variants... unless you build the entire set from scratch with variants this way but as you mentioned it is not a good workflow (which I agree). 

But neither is a whole bunch of sublayers for every asset that has variants. 

[cbrowneL7QTD]

I guess another question is , can I make a variant usd that can be refernced in under a Def? NOT a layer?

[cbrowneL7QTD]

OK after some digging, if reference in the JarGeom.usd under a new def in a whole new blank stage, new maya scene file etc and even new maya project... That Geom comes in with a variant, by itself. So in theory you can have variants on a geom usd by itself and be brought in under def's that maintain the variants. So my question is how do I create this?

Unfortunately the jar is not ascii so I can't see the text otherwise it would be much easier. Any suggestions? 

[Christoph_Schaedl]

As i mentioned above we use Bifrost. Take a look at the assets sample scene on the Bifrost discord.

https://discord.com/channels/872260298508222534/876728898036039701/1030569967390838866

[Christoph_Schaedl]

Here the nodes you need for the variant. You can download them in the link above.