Hi everyone and professor, I am new to modeling and I have the difficulty modeling this: I have a finger like in the attached images. I need to model it so that sometimes it can be stiff or soft (based on a control input). When it is stiff, the finger's movement on x-axis can drag along the bumps below it. When it is soft, it will act as a normal string with a mass hanging below. Right now, I can model the two cases separately by modeling the finger as a hinge joint around y-axis with (hard case) and without (soft case) an position actuator. However, I need to combine them. Could you guys give me some advice? Thanks! Hai.