Motion paths¶

A motion path is a visual curve in the canvas showing the trajectory of an animated placement's translate channel. Two features ride on it: visualization (see the path the placement will follow) and constrain-to-path (replace translate keys with a curve to follow).

Visualize¶

With an animated placement selected, Animate > Motion Paths > Show draws a curve in the View Panel passing through every keyed position. Tick marks along the curve show key positions; spacing between ticks indicates speed (close ticks = slow, far ticks = fast).

Useful for catching:

A trajectory that pops backward between keys.
Curves that ease out too sharply.
Unintentional bumps in what should be a smooth path.

Animate > Motion Paths > Hide removes the overlay.

Edit-in-place¶

With Show on, drag the small key handles directly in the View Panel to reposition the underlying translate keys. The keys on the time slider update in real time; the placement's animation follows.

Useful for "this descent path needs to swing wider here": drag the midpoint and the in/out tangents adjust automatically.

Constrain to a curve¶

Animate > Motion Paths > Attach to Curve… opens a small dialog asking which curve to follow. Pick any Bezier or NURBS curve from the project; the placement removes its translate keys and instead animates the curve's t parameter (0..1) over the timeline.

Now keying t from 0 to 1 over 60 frames moves the placement along the curve's entire length over that duration. Easing applies to t, not directly to position, so a slow-in / slow-out on t produces the same on the position automatically.

The Butterfly Banner tutorial's descent could be authored this way: draw a gentle S-curve from offscreen to the center, attach the butterfly placement, key t from 0 → 1 with cubic ease-out.

Constraint properties¶

Property	Effect
t	The animatable parameter (0..1)
follow_tangent	Rotate placement so its forward axis follows the curve direction
up_axis	Which placement axis is "up"; matters with follow_tangent
world_up	World vector used to compute roll
bank	Add a banking rotation proportional to curve curvature

follow_tangent is the difference between "a butterfly drifting along a path" (off: orientation independent of motion) and "a fighter jet flying along a path" (on: orientation locked).

Detach¶

Animate > Motion Paths > Detach from Curve un-constrains the placement, leaving its translate channel back in direct-key mode. The current t value is sampled to produce a single translate key at the current frame.

Use with rigs¶

Motion paths combine cleanly with rigs: attach the root joint to a path; the rest of the chain follows via the bind. The IK handles can independently animate to control the body's pose as the rig sweeps along the curve.