SimMechanics Reference Frame Orientation

Hi there. I am working through "How to build a model" example of the second generation SimMechanics examples, and cannot figure out how the Reference frame works. How is the orientation determined? I just cannot figure out how this is done. Where does it inherit the orientation from because it does not seem to be explicitly defined anywhere?

Answer 1

[Steve Miller]

The orientation of a reference frame block will be relative to the frames it is attached to. If you attach it to the World Frame with a Rigid Transform with no offset in position or orientation, then it will be oriented and located at the same spot as the World Frame. If you connect it to the World Frame via a 6-DOF Joint, at the start of simulation it will likely be oriented as the World Frame, and if it is attached to an inertia that can move due to gravity (such as a pendulum), as the simulation evolves the orientation of the Reference Frame may change.

--Steve