This is an example of how one would project a heel marker, RHEEL on the floor or X-Y plane of the laboratory. The ML, AP, Axial offsets basically say keep the RHEEL coordinates for X and for Y the same and change the Z coordinate to 0.

NOTE: This landmark will not be tracked using the target. For example, you will notice that if you do not check calibration only, the landmark will appear stationary in your dynamic trials. If you would like to create a landmark at a specific height which is tracked using the specified height, you can project a landmark (such as RHEEL) onto the plane defined by three targets (for example, LAB_O, LAB_X and LAB_Y). An example of projecting a landmark onto a plane can be found here.