Transform Cache Constraint

The Transform Cache Constraint streams an animation from an Alembic or USD file. For example, it can apply a baked rigid body simulation to an object.

The constraint is automatically added when importing such a file. However, it only applies to transforms (location/rotation/scale of the whole object). For animations that cause deformation, the Mesh Sequence Cache Modifier is used instead.

Options

Transform Cache Constraint.

Cache File

Data-block menu to select the Alembic or USD file.

File Path

Path to the Alembic or USD file.

Sequence

Whether or not the cache is separated in a series of files.

Override Frame

Whether to use a custom frame for looking up data in the cache file, instead of using the current scene frame.

The Frame value is the time to use for looking up the data in the cache file, or to determine which to use in a file sequence.

Frame Offset

Subtracted from the current frame to use for looking up the data in the cache file, or to determine which file to use in a file sequence.

Manual Scale

Value by which to enlarge or shrink the object with respect to the world’s origin.

Velocity Attribute

The name of the Alembic attribute used for generating motion blur data; by default, this is .velocities which is standard for most Alembic files.

Note

The Velocity Attribute option is currently for Alembic files only.

Velocity Unit

Defines how the velocity vectors are interpreted with regard to time.

Frame:

The velocity unit was encoded in frames and does not need to be scaled by scene FPS.

Second:

The velocity unit was encoded in seconds and needs to be scaled by the scene FPS (1 / FPS).

Note

The Velocity Unit option is currently for Alembic files only.

Object Path

The path to the Alembic or USD object inside the archive or stage.

Influence

How strongly the constraint affects the object.