Legacy Reference

Exporting an Alembic Cache

Alembic distills complex, animated scenes into a non-procedural, application-independent set of baked geometric results. Specifically, it handles baked meshes and their materials, but not rigs or other procedural networks of computations.

Lumberyard allows you to export Alembic (.abc) cache files from Maya. Lumberyard then compiles them into compressed game asset (.cax) files using the Resource Compiler and imports them into the game using the GeomCache entity. In-game, the .cax files are then streamed off disk.


Deforming meshes can be exported along with their UVs and material assignments. However, multiple UV sets are not exported; only the default UV set is exported.

To export an Alembic cache from Maya

  1. In Maya, rename each material using a unique integer ID. Material names are scanned from left to right and the first integer found is used. For example: mat01_sphere, mat02_sphere, mat03_cube.

  2. In Lumberyard Tools, choose Tools, Prepare Alembic Materials.

  3. In Lumberyard Tools, under Material Export, choose Add Group and then enter a name. The name of this material group (.mtl) file must match the name of the exported Alembic (.abc ) cache file.

  4. Set the export path to any folder within your game directory, and then choose Export Materials.

  5. In Maya, select the geometry objects you want to export, and then in Lumberyard Tools, choose Tools, Export Select to Alembic.

  6. In Export Alembic for Geomcache, navigate to the same directory used to export the materials to, enter the same name used for the material group, and then choose Save.

Lumberyard imports Alembic caches using the GeomCache entity found in the Rollup Bar.

To import an Alembic cache to Lumberyard

  1. In Lumberyard Editor, choose New and then enter a name for the new level.

  2. In the Rollup Bar, on the Objects tab, choose Entity.

  3. Under Browser, expand Render. Select GeomCache, drag it into the level, then click to position the entity.

  4. Under Entity Properties, choose the folder icon for File, select the Alembic (.abc) cache file previously exported, and then choose Open.

  5. In Compile Alembic, change preset, compilation, and compression settings as needed, and then choose OK.

  6. In Running Resource Compiler, review and resolve any errors, and then choose Close.


Lumberyard automatically changes the File property to point to the compiled .cax file. If you modify the Alembic (.abc) cache file later, you'll need to recompile it into a .cax file. To do this from Lumberyard Editor, change the File property to point to the .abc file instead of the .cax file. You will then be prompted to repeat the steps in this section.