Alembic

The Alembic tab allows to bake out Simulation Cache Files edited with the Simulation Layout Tool and linked in a Crowd Render Proxy node as Alembic files. The Alembic files can store only baked geometry (skeletons and skeleton animations can not be exported in this mode.

Notice that, due to Alembic performances with deformable objects and the amount of geometry exported, the export can take a really long time and generate huge files which will not be easily reopened by other DCC application. Exporting in Alembic files is usually not recommended if you're dealing with more than 3-400 characters. Since version 7.2.2 the alembic export is multi-threaded (per character or frame, depending on the export mode) to improve export time, but the file writing will still bottleneck the process.

Alembic Tab

 
Enable Enable / disable the Alembic bake. All Crowd Entities stored in the Simulation Cache in the selected Crowd Render Proxies will be exported to Alembic files.
Output Directory Directory to which to export the Alembic files. It is possible to specify one directory per Crowd Render Proxy by manually setting each directory (separated by ";").
Output Mode

Defines how the Crowd entities will be baked to Alembic files. There are 4 possible output modes:

  • Export Geometry In One File: exports the baked geometry of each character for the whole time range in one file.
     
  • Export Geometry In One File Per Entity: exports the baked geometry of each character for the whole time range in one file per entity.
     
  • Export Geometry In One File Per Frame: exports the baked geometry of each character for the whole time range in one file per frame.
     
  • Export Animations In One File (as Point Cache): exports the baked skeleton of each character as a point cache for the whole time range in one file. The generated Alembic file can be loaded as a point cache within Houdini.

    Notice that this mode is only available for Golaem Character Files storing Geometry using the GCG File Format.
Geometry Tag Type of Character Geometry Files to use when the simulation is baked.
Thread count The count of threads used for Alembic Export, by default it is the logical thread count of the CPU
Group Fur Curves All the fur curves exported in alembic can either by exported all in a single alembic::OCurves node (grouped) or split in different ones. If reimported in Maya, grouped ones will display as a single transform and different shapes, split ones will display as different transforms.

Alembic Integration

As shading variation is not supported by Alembic, when Alembic Files including geometry are exported, Golaem Crowd adds Arbitrary Geometry Attributes to each Alembic mesh. Those User Properties are:

Shader Groups Name of the Shader Groups (separated with ";") defined in the Character Maker Geometry Tab for this mesh
Shader Attributes For each Shader Attributes defined in the Character Maker, a new User Properties and its corresponding value is created. The value can be varying at each frame if using a PPAttribute to feed the value of the Shader Attribute.


Exemple of Arbitrary Geometry Attributes of a mesh with one Shader Group and two Shading Attributes (bodyId is varying)

When the file is loaded with Maya Pipeline Cache Importer, the Arbitrary Geometry Attributes are stored in the Extra Attributes of each mesh.