I'm trying to model a finger, and I want the extensor to be essentially a spring connected across the back of the finger (no external actuation), and the flexor to be a tendon that I can pull on. I've ended up with what seem like reasonable data structures using spatial tendons, but the action shows a lot of lag. Before I spend a lot of time fooling with the parameters, I want to ask - are these the structures that I should be using, or should I use a different model? <tendon> <spatial name="FLEX" width="0.0005"> <site site= "FLEX_ORIGIN" /> <site site="FLEX_PRO_IN" /> <site site="FLEX_PRO_OUT" /> <site site="FLEX_MED_IN" /> <site site="FLEX_MED_OUT" /> <site site="FLEX_INSERTION" /> </spatial> <spatial name="EXTENSOR" width="0.0005" stiffness="10000"> <site site= "EXTENSOR_ORIGIN" /> <site site="EXTENSOR_PRO_IN" /> <site site="EXTENSOR_PRO_OUT" /> <site site="EXTENSOR_MED_IN" /> <site site="EXTENSOR_MED_OUT" /> <site site="EXTENSOR_INSERTION" /> </spatial> </tendon> <actuator> <position ctrlrange="-10.0 10.0" name="FLEX_driver" tendon="FLEX" /> </actuator>