Cache

Bakes the dense groom to an Alembic file on disk and plays it back, so heavy deformation evaluates once instead of on every frame.

What it's for

Cache is a terminal node — it sits at the end of the stack and captures the finished result. It exists for the cases where the groom has to be re-evaluated every frame and that evaluation is expensive:

• Armature deformation — hair following a rigged character
• Simulation — so you scrub a solved result instead of re-solving
• An animated scalp — a deforming or moving mesh underneath

Once baked, playback reads the Alembic rather than re-running the stack, so scrubbing the timeline is fast and repeatable.

Frame Range

Use Scene Range

Bake the scene's own frame range. When on, the Start and End values below are ignored.

Start

First frame to bake.

End

Last frame to bake.

Step

Frame increment. 1 bakes every frame; higher values bake fewer and are useful for a quick look before committing to a full bake.

Output

Cache File

The Alembic (.abc) file to write. Leave it blank to use the default path, or use Browse… to choose where the file goes.

Actions

Bake

Bakes the groom over the frame range to the Alembic cache. This is the step that takes the time; everything after it is playback.

Free

Stops reading the cache and returns to live evaluation. Use this when you need to change the groom again — a cache is a snapshot, so edits upstream will not show while it is being read.

Where it goes in the stack

Cache belongs last. It captures whatever the stack produces, so anything you want in the bake has to be above it.

Tips

• Bake late. A cache freezes the groom, so bake once styling is settled — otherwise you will spend the day re-baking.
• Step through a coarse bake first. A Step of 4 or 5 gives a quick read on motion before you pay for every frame.
• Free before editing. If changes upstream appear to do nothing, the cache is probably still being read.
• The file is real. Alembic on disk can be handed to lighting or another department directly.