I'm trying to simulate an inelastic string that pulls on multiple joints (think a finger, where the string is anchored in the tip and runs the length of the finger. I'm currently trying to model this with a fixed length tendon - ie, a spatial tendon passing through sites on the bodies that are connected by the joints - and constrained by an equality of the form <equality> <tendon tendon1="my_string" /> </equality> I pull on the string by attaching a small mass to the end of the string, and moving the mass with a simple positional actuator. What I'm seeing is a huge amount of springiness in the response. Since I'm using a fixed length tendon I surmise that we're dealing with constraint violations, and I've attempted to manipulate solref and solimp to tighten the response. That's helped, but not enough. A few questions: - Is this a reasonable model for what I'm trying to do? - If so, what am I doing wrong? Am I simply not being aggressive enough with solref and solimp, or is there something else I should do? - If not, what model should I be using?