Create 3D curve for use with animated paths, IK Spline constrains, and more.
To create a 3D curve:

Asset browser showing the 3D Curve is selected
The cursor becomes a cross hair.

Viewer window displaying cursor and keyboard shortcuts for 3D Curve

Creating a 3D Curve
(Optional) Use the middle-mouse button or scroll wheel to add a vertex between the points.
(Optional) Click the right mouse button to add a vertex at the start point.
The green line represents the 3D curve. It also shows the 3D Curve is selected.
To edit a 3D Curve or create an animated path using a 3D Curve, see: