Property contribution wrt volume element

[bgpeyton]

It would be interesting to have a code chunk which checks the contribution to rotation (or energy, etc) as a function of the distance between fragments. For the two-body fragments this makes sense; however, for higher-body fragments this would not work. What could be done, however, is to see the contribution within a three-dimensional volume element or something similar. I will refine on this idea at a later time.