Probably greater than 4 out of 5 sessions has me reaching for Rhino’s Volume command:
Analyze > Mass Properties > Volume
Presuming the Rhino document started out in millimeter settings, the Volume command will likewise report in cubic millimeters. So in a result where I get “Volume=250 cubic millimeters” That should translate to 0.250 cubic centimeters.
Numerous sites suggest that a cube of 14k gold measuring 1 centimeter in all directions weigh approximately 14.4 grams.
(Sidenote to non-jewelers: Karat is a designation of gold’s purity. 24k designates a virtual total composition in gold. 14k could be elaborated as 14 divided by 24 – or 58.5% pure gold alloyed with something else to increase durability. 18k is 75% gold. 10k is 44% gold.)
Most north American jewelry slated for the showcase is usually either 14k or 18k. That’s why scripts like the above, while appreciated, doesn’t completely finish what Rhino jewelry users are after.
Again taking the example result of 0.25 cubic cm, multiply it by 14.4 and that gives a rough approximation of how many grams of 14k gold the object may use.
A cubic cm of platinum is roughly 23.8g
A cubic cm of silver is roughly 10.4g
Ideally, my wishlist item for RhinoWin and RhinoOSX would be a persistent window (like Control Panel of Flamingo nXT) that’d allow me to click on various nurbs/mesh/STL objects in the scene and it’d provide a spreadsheet-like calculation showing estimated weights for 3 or 5 materials. Each material would be selectable via pull-down (10k, 14k, 18k, platinum, silver, feathers, etc) but would also allow for a custom entry provided the user knows the exact cubic weight of that material (ie, 3D print a centimeter cube and weigh it for the specific resin I use) Jewelers would probably find a pennyweight option helpful, but then to be useful to a wider audience, the calculated weight would be available as a pull-down to find grams, ounces, pennyweight, pound, etc. If this plug-in were even smarter, it’d figure out the proper weight for objects that overlap in my scene before I commit to booleaning them.