Getting shapes volume/center of mass/... is too slow.

[PaddleStroke]

Getting shapes volume/center of mass/... is too slow.

[wwmayer]

This is almost instantaneous on a single simple object, but it becomes too slow on many occasions :

This depends on the complexity of an object. It can even take several seconds for a single object.

The property would just need to be generated once on recompute.

But this makes it worse for everybody else. For them it makes the recompute always slower independent on whether the value is later used or not.

As a bonus, if App::Parts could also have these properties, showing the sum of the Part::Features' properties within.

Storing sums makes only sense for Area and Volume but for CoM, MoI, ... it doesn't.

[PaddleStroke]

But this makes it worse for everybody else. For them it makes the recompute always slower independent on whether the value is later used or not.

Hmm I suspected this. It is unfortunate.
But perhaps the time to compute those is only a fraction of the time of recompute? If it adds 2% of time to recompute this could be acceptable. If it adds 70% then it's obviously not acceptable.

Storing sums makes only sense for Area and Volume but for CoM, MoI, ... it doesn't.

Saying sum was a simplification, but you can definitely find the CoM of a App::Part. For MoI I'm not sure but I guess the same is true.