To append to a geometry cache
A geometry cache is created for the frame or range of frames specified in the Append to Cache Options window and is added or appended to the enabled cache.
If the appended cache frames overlap in time with the enabled geometry cache, then they are automatically blended with that cache. However, if there is a gap in time between the enabled geometry cache and the appended cache frames, then the gap is linearly interpolated and no cache data for the gap is saved to the appended cache.