Rig drivers properties

The rig drivers family: a rig layer's driver influences - the weight of each driver's writes, percent (0..100), addressed by driver id. A driver maps its inputs through a range, a curve and its conditions onto its targets (or blends its placed poses); the influence scales the result - at 0 the driver writes nothing, at 100 it writes whole, and in between its targets lerp from their own value toward the driver's. Every pattern reads, keyframes AND drives: a script fading a driver's influence hands its targets back to their own keys over time.

Every pattern below is readable from scripts through prop() and layer.prop(); ids in a pattern (like <effect_id>) stand for the entity's real id. Every pattern here is in the drive set: scripts may WRITE each one with set() or a single-output return, per frame.

Worked examples#

A rig layer's DRIVERS map inputs onto targets (RIG-W4 POSE): each reads its input keys through a range, a curve and its conditions and writes its output keys (or blends its placed poses), and rig.drivers.<driver_id>.influence - percent (0..100) - scales what it writes: at 100 the driver writes whole, at 0 nothing, and in between its targets lerp from their own value toward the driver's. The influence reads, keyframes AND drives; the driver's other members (inputs, outputs, curve, conditions, placements) are statics that change through the driver commands.

Worked example: Fade the wrist driver out#

The scene. A Stage comp with a one-bone Wrist rig at (320, 180) - the Hand bone heading right for 100 px - carrying a Wave slider property (0..1, resting at 1) and a Wave to wrist driver that maps the slider onto the Hand's rotation, -30 to 30 degrees; and a Paddle solid rigidly bound to the Hand, so the bone's driven turn swings it about the wrist.

• The comp Stage: 640 by 360 at 25 fps, 100 frames (4 seconds).
• Wrist: a rig layer, at [320, 180].
  • The skeleton: Hand (bone_1, a root) from [0, 0] at 0 degrees for 100 px.
  • The properties: Wave (slide_1, a slider from 0 to 1, resting at 1).
  • The drivers: Wave to wrist (driver_1): rig.properties.slide_1.value 0..1 onto rig.bones.bone_1.rotation -30..30.
• Paddle: a solid layer, at [320, 180], 100 by 40, filled #4d9de0.
  • The rigging stack: rigging_1 - a rigid binding to the Wrist rig's Hand.

The script. Add a project script named Driver fade and paste:

export const outputs = ["layer_1:rig.drivers.driver_1.influence"];

export function frame() {
  return linear(time, 0, 2, 100, 0);
}

Line by line:

• Line 1: One output: the INFLUENCE of the Wrist rig's Wave to wrist driver. rig.drivers.<driver_id>.influence is a percent - at 100 the driver's writes land whole (the Wave slider at 1 turns the Hand 30 degrees), at 0 it writes nothing and the Hand keeps its own rotation (0 degrees, level).
• Line 4: linear() maps the first two seconds onto 100 down to 0 and holds 0 after that: the Hand's rotation lerps from the driver's 30 degrees toward its own 0 as the influence fades, so the Paddle settles from its clockwise turn to level over two seconds. The value must stay inside 0..100 - a script that returns 140 refuses with type_mismatch, never a clamp.

What you see. The Paddle starts turned 30 degrees clockwise (the driver at full influence) and settles to level over two seconds, then holds - at one second the influence reads 50 (the Paddle at 15 degrees), from two seconds on it reads 0.