Sometimes it is valuable to track (over time) the XYZ coordinates of a single point relative to a user-defined anatomical coordinate system. This is useful, for example, if soft tissue markers have been implanted and their movement relative to a coordinate system defined by the bones is of interest.
- Press the gLoc axes button in Maya XROMM Tools to create a Giant Locator
- Move and rotate the Giant Locator into position to define the Anatomical Coordinate System (ACS)
- Parent the giant_locator to the reference object (usually a bone)
- Create a regular locator for the point you want to track. Move it to the position you want to track (holding down the V key while moving the locator will snap it to the nearest point on a mesh).
- Parent regular locator to the animated movement of interest (usually either a bone or an animated locator)
- Press the oRel button in Maya XROMM Tools to output Relative Motion