Been doing some research on methods to apply spatial transformations to animated objects.
The main problem I was trying to solve here is how to offset animated transforms while maintaining sparse curves - the obvious solution is to add another transform as a parent and simply offset that but I was curious if there was a way to do it directly on the animated transform.
The resulting tool is still work-in-progress but I wanted to get the first version out there and see if people may have suggestions for improvements.
I chose to approach this using OpenMaya for speed reasons, using the cmds library works as well but doesn't allow you to query values using a time context, rather having to set the currentTime which is much, much slower.
time_context = OpenMaya.MDGContext(OpenMaya.MTime(frame))
matrix_object = plug.asMObject(time_context)
fn_matrix_data = OpenMaya.MFnMatrixData(matrix_object)
matrix = fn_matrix_data.matrix()
Another benefit is being able to directly manipulate animation curves, for animated objects.
m_plug = m_dag_node.findPlug(attribute, False)
m_source = m_plug.source()
if m_source.isNull:
return
m_source_node = m_source.node()
if not m_source_node.apiTypeStr.startswith('kAnimCurve'):
return
fn_curve = OpenMayaAnim.MFnAnimCurve(m_source_node)
fn_curve.addKey(OpenMaya.MTime(input), value)The main outstanding issue are the that it doesn't account for rotation order changes and the way it handles rotations over the 180 degree threshold, it's internally using matrices so this information gets lost during calculations. I've implemented an experimental flipping filter that works quite well but I'm continuing to do research on how to improve it when I have some time.
Full code available on my github: https://github.com/mvanneutigem/maya_tools