Skip to main content

Xgen for Maya

OpenPype supports Xgen classic with the follow workflow. It eases the otherwise cumbersome issues around Xgen's side car files and hidden behaviour inside Maya. The workflow supports publishing, loading and updating of Xgen collections, along with connecting animation from geometry and (guide) curves.

Setup​

Settings​

Go to project settings > Maya > enable Open Workfile Post Initialization;

project_settings/maya/open_workfile_post_initialization

This is due to two errors occurring when opening workfile containing referenced xgen nodes on launch of Maya, specifically:

  • Critical: Duplicate collection errors on launching workfile. This is because Maya first imports Xgen when referencing in external Maya files, then imports Xgen again when the reference edits are applied.
Importing XGen Collections...
# Error: XGen:  Failed to find description ball_xgenMain_01_:parent in collection ball_xgenMain_01_:collection. Abort applying delta: P:/PROJECTS/OP01_CG_demo/shots/sh040/work/Lighting/cg_sh040_Lighting_v001__ball_xgenMain_01___collection.xgen  #
# Error: XGen:  Tried to import a duplicate collection, ball_xgenMain_02_:collection, from file P:/PROJECTS/OP01_CG_demo/shots/sh040/work/Lighting/cg_sh040_Lighting_v001__ball_xgenMain_02___collection.xgen. Aborting import.  #
  • Non-critical: Errors on opening workfile and failed opening of published xgen. This is because Maya imports Xgen when referencing in external Maya files but the reference edits that ensure the location of the Xgen files are correct, has not been applied yet.
Importing XGen Collections...
# Error: XGen:  Failed to open file: P:/PROJECTS/OP01_CG_demo/shots/sh040/work/Lighting/cg_ball_xgenMain_v035__ball_rigMain_01___collection.xgen  #
# Error: XGen:  Failed to import collection from file P:/PROJECTS/OP01_CG_demo/shots/sh040/work/Lighting/cg_ball_xgenMain_v035__ball_rigMain_01___collection.xgen  #

Go to project settings > Deadline > Publish plugins > Maya Submit to Deadline > disable Use Published scene;

project_settings/deadline/publish/MayaSubmitDeadline/use_published

This is due to temporary workaround while fixing rendering with published scenes.

Create​

Create an Xgen instance to publish. This needs to contain only one Xgen collection.

OpenPype > Create... > Xgen

You can create multiple Xgen instances if you have multiple collections to publish.

note

The Xgen publishing requires a namespace on the Xgen collection (palette) and the geometry used.

Publish​

The publishing process will grab geometry used for Xgen along with any external files used in the collection's descriptions. This creates an isolated Maya file with just the Xgen collection's dependencies, so you can use any nested geometry when creating the Xgen description. An Xgen version will consist of:

  • Maya file (.ma) - this contains the geometry and the connections to the Xgen collection and descriptions.
  • Xgen file (.xgen) - this contains the Xgen collection and description.
  • Resource files (.ptx, .xuv) - this contains Xgen side car files used in the collection and descriptions.

Load​

Open the Loader tool, OpenPype > Loader..., and navigate to the published Xgen version. On right-click you'll get the option Reference Xgen (ma) When loading an Xgen version the following happens:

  • References in the Maya file.
  • Copies the Xgen file (.xgen) to the current workspace.
  • Modifies the Xgen file copy to load the current workspace first then the published Xgen collection.
  • Makes a custom attribute on the Xgen collection, float_ignore, which can be seen under the Expressions tab of the Xgen UI. This is done to initialize the Xgen delta file workflow.
  • Setup an Xgen delta file (.xgd) to store any workspace changes of the published Xgen version.

When the loading is done, Xgen collection will be in the Xgen delta file workflow which means any changes done in the Maya workfile will be stored in the current workspace. The published Xgen collection will remain intact, even if the user assigns maps to any attributes or otherwise modifies any attribute.

Updating​

When there are changes to the Xgen version, the user will be notified when opening the workfile or publishing. Since the Xgen is referenced, it follows the standard Maya referencing system and overrides.

For example publishing xgenMain version 1 with the attribute renderer set to None, then version 2 has renderer set to Arnold Renderer. When updating from version 1 to 2, the renderer attribute will be updated to Arnold Renderer unless there is a local override.

Connect Patches​

When loading in an Xgen version, it does not have any connections to anything in the workfile, so its static in the position it was published in. Use the Connect Geometry action to connect Xgen to any matching loaded animated geometry.

Connect Guides​

Along with patches you can also connect the Xgen guides to an Alembic cache.

Usage​

Select 1 animation container, of family animation or pointcache, then the Xgen containers to connect to. Right-click > Actions > Connect Xgen.

Note: Only alembic (.abc) representations are allowed.

Details​

Connecting the guide will make Xgen use the Alembic directly, setting the attributes under Guide Animation, so the Alembic needs to contain the same amount of curves as guides in the Xgen.

The animation container gets connected with the Xgen container, so if the animation container is updated so will the Xgen container's attribute.

Rendering​

To render with Xgen, follow the Rendering With OpenPype guide.

Details​

When submitting a workfile with Xgen, all Xgen related files will be collected and published as the workfiles resources. This means the published workfile is no longer referencing the workspace Xgen files.