Bake types¶
Six entries in the Animation Type dropdown. Each takes a different source and has its own material node.
| Type | Source | Decode node | Playback |
|---|---|---|---|
| Rigid Body (Compound) | Physics actors / Geometry Collection | VAT RBD Decode Compound | One static mesh |
| Rigid Body (Instanced / ISM) | Physics actors sharing one mesh | VAT RBD Decode ISM | GPU-instanced |
| Soft Body | Skeletal mesh / Chaos cloth actor | VAT Soft Body Decode | One static mesh |
| Soft Body (Anim Sequence) | Skeletal Mesh + Anim Sequence assets | VAT Soft Body Decode | One static mesh |
| Particle | Niagara system actor | (Niagara data interface) | Niagara emitter |
| Fluid (Geometry Cache) | Alembic Geometry Cache actor | VAT Fluid Decode | One static mesh |
Rigid Body (Compound)¶
For fracture and destruction — anything made of pieces that move and rotate as rigid units.
Source: select one or more static mesh actors with physics enabled, or a single Chaos Geometry Collection actor, then click Use Selected.
Produces: one combined static mesh containing every piece, plus position and rotation textures.
Works with any simulation, including fractured Geometry Collections where every piece is a different shape.
Rigid Body (Instanced / ISM)¶
The same simulation, played back GPU-instanced: one mesh drawn many times instead of one large combined mesh. Cheaper for large piece counts.
Requires all source actors to share the same static mesh at the same scale, and at least two pieces. If that isn't true, the bake falls back to Compound and logs a warning explaining which condition failed — the bake still succeeds, it just isn't instanced.
Geometry Collections can't be instanced (their pieces are all unique shapes); use Compound for those.
Playback uses the VATRBDInstancedComponent rather than a plain static mesh component. Place it
at the bake's origin — the material drives every piece out to its position from there.
The Instanced node needs one extra wire
Its PieceIndex input must be fed by a PerInstanceCustomData node (index 0). Unreal only
uploads per-instance data to the GPU when that node is physically present in the graph, so
without it every instance reads the same piece and they all stack on top of each other.
Soft Body¶
For cloth and deforming skinned meshes — anything where individual vertices move independently.
Source: one skeletal mesh or Chaos cloth actor. The bake captures the simulation running in the editor, so the actor must actually animate over the frame range you set.
Captures skinning, morph targets and cloth together.
Soft Body (Anim Sequence)¶
An animation cycle baked straight from assets — the crowd and background-character case.
Source: a Skeletal Mesh and an Anim Sequence asset (not a level actor). The mesh and sequence must use compatible skeletons.
Unlike every other type, this never starts a play session. Each frame is sampled at an exact time, so the result is identical every time you bake it, and Start Frame genuinely seeks into the sequence.
Output is identical in form to a Soft Body bake and uses the same VAT Soft Body Decode node.
Particle¶
For Niagara systems — baked particle positions replayed on the GPU.
Source: one Niagara system actor.
Enable Requires Persistent IDs
The emitter must have Requires Persistent IDs enabled, or particle identity isn't stable between frames and playback will be wrong. The bake warns you if it's missing — enable it and re-bake.
Produces a position texture and a data asset only — no mesh. Playback goes through a Niagara emitter; see Niagara particles.
Particle bakes are 16-bit or 32-bit float only; the 8-bit option isn't offered.
Fluid (Geometry Cache)¶
For surfaces whose topology changes every frame — liquid and smoke meshes imported from Alembic.
Source: one Geometry Cache actor. Multi-track caches bake the first track only.
Playback snaps to whole frames — there is no blending between frames, because the surface is a different shape each frame. Bake at a high frame rate for smooth motion.
This type is memory-hungry. For a single hero effect a Geometry Cache is often the better choice; Fluid VAT wins when you need many instances or GPU-only playback.
Fluid bakes are 16-bit or 32-bit float only. At 16-bit the surface can crack, more visibly on scaled-up actors — switch to 32-bit if you see it.