- Free Joint This joint type is used to link two segments that do not share any markers, and which can therefore move freely relative to each othermove totally independently of each other (eg, left and right foot). It is a 6 DOF joint with full translational as well as rotational freedom. It is used for the root segment to allow it to move freely with respect to the global origin; you cannot change the root's joint type.
- Ball Joint This 3 DOF joint, with full rotational (but not translational) freedom, is used to link two segments that share one marker, and which can therefore rotate freely around all three axes with respect to each other, but cannot translate. This joint type has the position of the child segment defined from the position of the parent joint, but its orientation can vary freely.
Use Ball Joints (3 DOF) for segments that share one marker and Free Joints (6 DOF) for segments that share none, often adjacent to each other both anatomically and as defined within the segment list. This is the preferred joint type to use when linking segments.
Hardy Spicer Joint A 2 DOF joint with two rotational degrees around two axes, namely the Y and Z axes of the parent joint. This joint type has two perpendicular vectors defining the directions of the two axes around which the joint can rotate.
Hardy Spicer (2 DOF) and the Hinge Joint (1 DOF) are advanced joint types and we recommend that you do not use them without first contacting Vicon Support.
- Hinge Joint This 1 DOF joint allows rotation around a single axis only, and should be used to link two segments that share two markers. The hinge axis is aligned with the two markers that are shared.