I have 2 faces that I wish to plot the angular displacements for against each other or both against the same frame rate. The 2 faces sit 90° apart as they are pivoted through a bell crank. the 1st crank is attched to a pedal (the longer crank) whilst the 2nd crank is attached to an actuator. I get a great result for the pedal crank from -13° to + 17° which is what I'd expect to see but the actuator crank seems to be coming out with some strange results such as 77° to 107°, whilst the angle that it's sweeping through seems to be correct (30°) it's start and end figures seem to be in the wrong place, I'd like, to see -15° to + 15° from it's midposition.

The block that has been inserted has no relation to the linkage system it is simply there for me to pick faces from to try and plot a different angular displacement result. Does anybody know how to change the position at where the Motion study takes it angular dispalcement from?