hi, I know, I am already too old for posting feature requests. I was just thinking that I miss the ability to damp the speed of masses in msd. right now I am using something like mass mass1 1 100 0 0 mass mass2 1 100 1 0 link l mass1 mass2 10 10 0 0.01 0 link l 1 I want that the masses reject each other within a certain range and then just reduce speed and stop if the speed is lower than a certain threshold. probably I should try to implement this myself. but maybe I am only missing something. thanks, marius.