I have two similar objects that pivot about the same axis in an assembly. At a similar radius there is a 3D Sketch of a line between the two similar objects. The end points of this line are defined but the length is not defined. When I rotate one object and rebuild the assembly the line rotates. However, I cannot get the line to move using the motion study. How do I get the line to move each frame with the motion study by just putting a motor on the object?