Work with USD Data and Maya Data interchangeably

Working with USD data and Maya data in conjunction and translating between the two enables you to leverage both USD and all of Maya's animation tools. To amplify your workflow with the mixed data model of Maya and USD data, you can use the Maya Outliner to translate data back and forth between Maya and USD.

Tip:

When translating data, track the progress of your change with the progress bar in the bottom left corner of your screen.

Starting with USD Data

Using the Outliner and the Outliner Contextual Menu, you can right-click any prim in the Outliner and choose to Edit as Maya Data or Duplicate as Maya Data.
You can also access the Marking Menu in the Viewport with a selected prim to activate the option to Edit as Maya Data.

Important: The option to Edit as Maya Data/ Duplicate as Maya Data will only appear on primtypes that have import/export translators. If any primtype has a set of translators (one for import, one for export), the option to Edit as Maya data will appear. For example, the primType BlendShape doesn't have translators, so the option will not appear when a Blendshape PrimType is selected. However, if you are an advanced user of the USD pipeline and your studio has created custom translators, you will be able to access the Edit as Maya Data/ Duplicate as Maya Data option.

PrimTypes that currently have registered import/export translators can be found on the official MayaUSD GitHub repository. Remember that for a PrimType to have Edit as Maya Data functionality, it requires both an import and export translator.

Example C++ prim translators:
- cameraWriter.h (export)
- cameraReader.cpp (import)

Note: When Maya data is inside USD hierarchy (via Pull), the Maya data will inherit visibility from the USD ancestors. Going one step further, if the Maya pulled object is inside the USD data which is then inside a Maya hierarchy, the pulled Maya data will inherit the Maya data's visibility as well. Also, when you frame an ancestor of the Maya pulled data, the Maya data will be included in the frame. Going further, if the Maya pulled object is inside USD data which is then inside a Maya hierarchy, the pulled Maya data will be framed when the top level Maya data is framed.

Edit as Maya Data

Pull/Push workflow

Select a prim > right-click > Edit as Maya data (PULL)

Tip: Select the "" beside Edit as Maya data to configure your options. This box opens up the standard Maya options from the import dialog. Here you can configure plug-in configurations and customize an import with prim readers, shader readers, chasers, and more. This gives you and your studio greater control over the Edit As Maya Data workflow.
Once a prim is pulled the following occurs:
1. USD Layer Editor: The session layer is edited with application state data. To unhide your session layer and learn more about working with session layers, see USD Layer Editor Options. This allows edits to be cleared easily as data interchanges between Maya and USD. Your target layer in the USD Layer Editor will remain unchanged until you Merge Edits to USD.
2. Viewport: Your chosen prim is deselected once data caching/translation into Maya data is complete.
3. Outliner: Your pulled data branch lines will be grey and your pulled object will be italicized. Note that all decendant nodes are pulled as well. Once pulled, the maya object and children are all locked.
You can undo and redo edits while manipulating pulled data.
The following options are available for once you finish editing as Maya data:
- Select Merge Maya Edits to USD (PUSH), the following occurs:
  - The connected prim with edits are merged back to USD. Once pushed, the connected prim is visible in the viewport containing the new edits. The new edits on the prim are authored on the layer that has the editTarget.
    
    After merging your edits to USD, if you go into the same prim and select Edit as Maya Data again, you will not see the construction history from the previous pulled Maya object.
    
    Important: When merging edits to USD, all edits will be placed on your current edit target layer. The session layer will be cleared of all application state data. Also, if 'Merging to USD' on a stronger layer (including the session layer), the prim is specified as an over. If you are 'Merging to USD' on a weaker layer, the prim is specified as a def.
- Select Discard Maya Edits (CLEAR), the following occurs:
  - The pulled Maya object diappears and in it's place in the USD hierarchy you will see the original prim that was connected. This action is undoable.

Important: When you pull a prim into Maya data, a new set appears in the Outliner called usdEditasMaya. If you have an orphaned Maya object (if a USD ancestor is deactivated/deleted, switched via a variant or unloaded from your scene via payloads), there will be limited options for your usdEditAsMaya set. You will only be able to Discard Maya Edits in this case. Orphaned data appears greyed out and with a red x icon on the pulled prim in your usdEditAsMaya set.

Note: When Maya data is inside a USD hierarchy (via Pull), the Maya data will inherit visibility from the USD ancestors. Going one step further, if the Maya pulled object is inside the USD data which is then inside a Maya hierarchy, the pulled Maya data will inherit the Maya data's visibility as well.

The Pull/Push methodology & common use cases

Pulling and pushing your data back and forth in MayaUSD allows you to access twice the workflows. This process works thorough the backend like merging and branching edits; a cached version of edits are created locally on your drive and once complete, are discarded or merged back (with undo feature implemented in the process). This feature enables (but is not limited to) the following edits for USD data pulled into Maya data:

Editing and adding UV tags
Sculpting point positions
Modifying a material assignment
Animating a camera

Duplicate as Maya Data

Copy workflow

Select a prim > right-click > Duplicate as Maya data (COPY)
Once a prim is copied the following occurs:
1. Importing: All aspects of your selected prim are imported as Maya data. The USD data gets imported into Maya nodes, independent of the import options.
2. Interface: Your newly created Maya node is selected in the Outliner and Viewport.
Undo is supported in this workflow and there are no edits within the USD Layer Editor.

Copy methodology & use cases

The copy workflow enables you to leverage USD into your Maya toolset by providing an extensible and funtional reference point for your work. This feature enables (but is not limited to) the following capabilities for Maya data as a result of USD data:

Using USD data as a reference for Maya modeling data
Using USD data and bringing it into Maya data to create a live surface
Debugging a translation

Starting with Maya Data

Duplicate as USD data

If a stage node exists in your Maya scene file (see Create a USD Stage), the Outliner Contextual Menu will have the option of Duplicate as USD data appear on your currently selected Maya node. Using the Outliner and the Outliner Contextual Menu, you can right-click a Maya node when a stage has been created in the Outliner and choose to Duplicate as USD Data.
- If multiple stages are present in your scene, you will be able to select and choose which stage to place the duplicate of your Maya node in.
You can also access the Marking Menu in the Viewport with a selected Maya node to activate the option to Duplicate as USD Data.

Copy workflow

Select a Maya node (when a USD stage is present in the scene) > right-click > Duplicate as USD data (COPY)
1. If multiple stages are present in the scene, you can select which one to duplicate the data into from the stages presented.
Select Options... to choose the way your Maya objects are exported to USD. The Duplicate as USD Data window appears with the same options as the typical export options; including Geometry, Materials, Animation and Advanced settings. In this window you can set your preferences for the export. After building out the scope of your options, select Apply to apply your settings or Close to cancel the operation. Important: When you duplicate edits to USD, the options in this dialog that you select can persist in Maya memory from the last time you exported and even in your last Maya session. Ensure you check these settings each time as your selections can be saved in Maya. You can also select Edit from the top left menu in this dialog to Save Settings or Reset Settings for any Maya data export processes.
Once a maya node is copied, the following occurs:
1. Exporting: The Maya selected object in its entirety gets exported to its USD equivalent, which is created at the root of the stage.
2. The original Maya object remains as it was.

Copy methodology & use cases

The copy workflow enables you to leverage USD into your Maya toolset by providing an extensible and functional reference point for your work. This feature enables (but is not limited to) the following capabilities for USD data as a result of Maya data:

Using Maya modeling data as a reference for USD data
Creating an extensible workflow from an existing limited workflow in Maya
Debugging a translation

Push/Pull method limitations

Important:

USD data is unaware of Maya data inside in the mixed-data model. Thus, when Maya data is inside a USD hierarchy, its visibility isn't inherited from its USD ancestors. Additionally, when Maya data is inside a USD hierarchy, reframing the Viewport on its USD ancestors will not include Maya data. Transforms can therefore misconfigure when animating pulled USD data.