Simulation data is not available with rigid groups?

Hi everyone,

I created a very simple motion study like this:

The study includes 2 cubes (A and B) which can slide on a surface. A linear motor pushes cube A forward.

After the simulation had been done, I added 2 plots for cube A: A trace path plot and a linear displacement plot.

This is the trace path plot:

And this is the linear displacement plot, which plots the relative displacement between a point in cube A and a point in cube B:

Everything's so far so good.

My problem is:

If I created a Rigid Group and then moved cube A into it, then no plot could be made anymore: There was no trace path in the trace path plot, and I couldn’t show the linear displacement plot as well.

If I moved cube A out of the Rigid Group and ran the simulation again, everything was back to normal.

Could you please explain to me what was happening? What’s wrong with Rigid Groups, or, is this an intended behavior of them? More generally, how can I create plots for a part which is inside a rigid group?

Thank you.

SolidworksMotion Studies