Some googling for "matrix to quaternion conversion" turned up http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/ which goes through the math and presents Java and C++ code for building a quaternion from a rotation matrix. Similar googling can be performed for "quaternion slerp" and "quaternion to matrix conversion".
really nice article thanks, thankfully XNAMath has a nice function XMQuaternionSlerp() so that will save me a ton of work;
The 4x4 matrix of an affine transformation is compose of a 3x3 matrix that represents a linear mapping (in the case of posture data this is a rotation) and a translation vector (a column to the right of the 3x3 matrix or a row below it, depending on whether you are using column vectors or row vectors). The other four components are always "0 0 0 1".
Ok so where do i get this rotation information if the only transformation information i have is stored in one matrix
Extract the rotation and the translation separately and convert the rotation to a quaternion (see JTippetts's post above).
thanks i was very clueless about how the different information was sorted in the matrix, any idea where the scaling information is