BRK (Break) modifies Smooth motion by decelerating speed to zero at each keyframe (a break), then starting again.

IGN (Ignore) allows selected parameter values to be ignored when calculating motion path.

SMTH (Smooth) provides a curved path between keyframes. The effect speeds up gradually as it leaves the first keyframe, and slows down gradually until it reached the last keyframe.

LIN (Linear) provides a constant rate of change between keyframes, with an abrupt change at each keyframe. Linear uses the shortest distance between two points to travel from one keyframe to another.

HOLD stops all motion between keyframes. The result of the motion shows when the next keyframe appears. HOLD looks like a video “cut,” from one keyframe to the next.