Gimbal for visualizing Euler (or Tait-Bryan) angles in FreeCAD.
A gimbal is a set of three hierarchical rotatable rings representing three possible axes of rotation, X, Y, or Z.
Different ring hierarchies, or rotation orders can exist.
In FreeCAD, this rotation order is x-y'-z" for intrinsic rotations, and z-y-x for extrinsic rotations (see Tait-Bryan angle conventions).
The gimbal hierarchy is as follows:
- the outermost ring represents the X rotation axis, in red.
- the middle ring represents the Y rotation axis, in green.
- and the innermost ring represents the Z rotation axis, in blue.
Each ring is affected by the rings on the outside of it.
Thus, the X ring rotates independenty, the Y ring is affected by X, and the Z ring is affected by both X and Y.
