Input point filters are invoked for all string and digitizer events when a point is being acquired. They can modify the final point position returned to the caller by AutoCAD and the ToolTip string displayed by AutoCAD.
Input point filters are processed before any input point monitors, but after all other input point computations are performed by AutoCAD. The output points are still subject to AutoCAD XYZ point filtering.
Only one input point filter can be active at a time.