Arcball is an input technique for 3-D computer graphics,
using a mouse to adjust the spatial orientation of an object.
In Arcball, human factors and mathematical fundamentals
come together exceptionally well. Arcball provides consistency
between free and constrained rotations using any
direction as an axis; consistent visual input and feedback;
kinesthetic agreement between mouse motion and object
rotation; and consistent interpretation of mouse position.
Attention to mathematical detail facilitates the tasks of
users and implementors. Users say that as a general-purpose
rotation controller Arcball is easier to use than its nearest
rival, the Virtual Sphere. It is also more powerful, and
simpler to implement.