Hi,
How to express the total mass of the system in the expression? So far I've attempted to use `body1.mass + body2.mass + body3.mass+ ...`, but this gave me error evaluating the solver variables.
Another question is, is there a way to input commands into the GUI so that its possible to check the values of these expressions? I see the HWC commancs, python window, and a Tcl Command window but so far neither of those respond to commands to these expressions.
Thank you,
Linn
