Hi Adriano. There are a couple of reasons why the heads were separated from the body. Unreal’s implementation of FBX into the engine will only support 8 influences per vertex. While this is sufficient for most game scenarios, it was too limiting when trying to achieve really nice facial performances on a character.
The separated head deployed a 201 joint facial rig with blendshapes and lattices to give animators to full advantage of Maya’s deformation capabilities. The deforming mesh, when exported as an alembic file was brought into UE4 as a skeletal mesh and streamed during playback in realtime. The character bodies, however, were FBX files who’s game skeletons were enhanced by ART v2.0 tools by adding additional leaf nodes that could be driven in engine by anim physics. The 8 influence limitation wasn’t a huge deal for the bodies.
Could the characters be entirely alembic cached? Sure. But then you’d loose all that secondary animation goodness that anim physics provides.
I’ll be giving a talk at Montreal Dev Days next Thursday (9/28) to discuss the Fortnite Pipeline. It will be recorded and made available after the event.
Brian J. Pohl
M&E Solutions Engineer - North America
Epic Games - Enterprise Team