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Mass Properties Tool is quite painful
AstroChuck
Member Posts: 2 ✭
The mass properties tool may be my third most used tool in Onshape, right after sketches and extrudes, and it's honestly quite painful.
The short version is that it is very slow to get a piece of information that other CAD tools have rapidly available. From a narrative perspective in say, Solidworks, clicking the mass properties tool will automatically select the complete file and promptly provide the requested mass properties.
In Onshape selecting the mass properties tool then requires additionally making a selection of what you'd like the mass properties of. Onshape's part studios make this seem like a good idea, as context makes it less obvious what you'd like the mass of, but in reality it just adds a bunch of clicks. In an assembly, I probably want the mass of the assembly. In a part studio, I probably want the mass of the part studio, and if I don't, I'll have to click the specific part anyway, so not default selecting everything is always a net negative on user clicks. Maybe the software could try and be clever in part studios and select the body most recently modified if nothing is selected. Once a selection is made you are treated to a spinny wheel in all cases while you wait for numbers to crunch. On larger models this is regularly more than 30s and not infrequently more than a minute. If you then close out and reopen the mass properties again, it takes just as long to recompute - hopefully you didn't just fat finger typing that number in somewhere else!
Once the mass properties are computed, you'll almost certainly be informed that "One or more parts do not have a material defined" which is a singularly unactionable error message (which parts?, how many? what fraction of the volume? does the part have an overridden mass in addition to no material?).
A hopefully concrete list of postive changes to the mass properties tool:
Cache computed values to reduce the delay in displaying recently computed values
Add a "dual unit" option to the mass properties tool (and measurement tool!) sometimes when dealing with vendor provided models you might be working in inches and mm or lbs and kgs. i.e Mass: 136.89 kg (301.79 lbs)
Using the mass property tool in an assembly auto-selects the top level assembly and starts computing mass immediately
Make it possible to create a mate connector at the center of gravity location.
List/Highlight/sort by parts with overridden masses or missing mass properties (might belong in the BoM view?)
Comments
I do fully agree with the above.
I'll add one more, though: Auto-highlight all volumes that have no material assigned. Open or refer to a place (BOM?) where this can be corrected in a straightforward manner. Add a default material option for new parts.