maspack.matrix contains a number classes that implement rotation matrices, rigid transforms, and affine transforms.
Rotations (Section A.1) are commonly described using a RotationMatrix3d, which implements a rotation matrix and contains numerous methods for setting rotation values and transforming other quantities. Some of the more commonly used methods are:
Rotations can also be described by AxisAngle, which characterizes a rotation as a single rotation about a specific axis.
Rigid transforms (Section A.2) are used by ArtiSynth to describe a rigid body’s pose, as well as its relative position and orientation with respect to other bodies and coordinate frames. They are implemented by RigidTransform3d, which exposes its rotational and translational components directly through the fields R (a RotationMatrix3d) and p (a Vector3d). Rotational and translational values can be set and accessed directly through these fields. In addition, RigidTransform3d provides numerous methods, some of the more commonly used of which include:
Rigid transformations are actually a specialized form of affine transformation in which the basic transform matrix equals a rotation. RigidTransform3d and AffineTransform3d hence both derive from the same base class AffineTransform3dBase.