Transform Cache Constraint

The Transform Cache Constraint is used to stream animations from Alembic or USD made at the transformation matrix level (for example rigid bodies, or camera movements).

When importing an Alembic or USD file, Transform Cache constraints are automatically added to objects with animated transforms. For time-varying meshes (so deforming animations), the Mesh Sequence Cache modifier is used.

Options

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

Controls the percentage of affect the constraint has on the object. See common constraint properties for more information.