How can I model a rolling-sliding motion like that of a knee joint?
1st open up my attached .jpg file. As it shows there are two parts as PART 1 & PART 2. I have fixed the PART 2. Then in assembly a tangent mate was added for this curved face & flat face as shown. Then a limit angle mate was added for indicated faces ( lets say max 90 min 0). Then a linear limit mate was added for the center plane of PART 2 & center of curved face ( lets say max 3mm min 0). In animation select a time key on time line (lets say 10s) and move the part 1. So there you should have sliding & rolling movement for 10s animation. I'm familiar with solidworks. So I have describe this base on solidworks. So you can match it with PTC. Hope it will works