Most games use a "hitch" preset (a simple loop). Calico uses a logic tree of 47 distinct knots. The system calculates the friction between rope strands. If the user drags the rope too fast, the system simulates a "burn" or a slip. This requires immense CPU power, but the real time feedback is uncanny.
Without real time processing, the bondage looks like plastic. With it, specifically with , the rope breathes. Real Time Bondage-------Calico