Hi all! Wondering if anyone has a trick to getting the exact dimensions and angles of an oddly shaped stone, without the use of a ridiculously expensive 3d scanner. I have been mostly wax carving but am now learning CAD, and have run into some issues where the stone hasn’t fit perfectly, especially when flush setting a fancy shape stone that isn’t perfectly symmetrical. I feel like there’s got to be a way?!
You can put it on a scanner and scan it and then import the image into a 3-D modeling software, but that’s just going to get you started.
The old-school approach would be with a micrometer and an angle gauge. Then you’d have to construct the stone in CAD using the measurements.
Hi,
i would take a photo of the stone, then bring it in to CAD software (background bitmap, i think)split the photo with a rect curve, then scale it to the correct length (or width).
you can adjust the transparency of the photo to fade it out, so that you can see your curves.
julie
wait…not bitmap…picture frame i think…
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If you scan it with a ruler on the scanning bed, you have an easy scale for the cad process
oh this is a great tip
There are plenty free bmp to dxf apps out there.
DXF is supported by most if not all CAD software.
hi,
you can also use orient 2 points, to “scale” the photo
ie: you draw a line curve for the actual length or width you want.
then trace the outline of the gem…then add/ draw a curve line centered on that gem curve
use the geometry to accurately snap (ie: intersect snap…perpendicular snap) the orient 2 points
julie
You might want to share the program you’re using. I use Rhino and there are different commands I believe. Or maybe these are ones I’m not familiar with!
Hi,
oh sorry, i neglected to mention that.
i am using Gemvision MatrixGold, which is built on Rhino…i am on Rhino 8 i think…i mostly surface model and so basically using Rhino commands within the MG interface…most commands are same…
julie
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Cool! I life learning new rhino commands.
Hi,
is there a “help” button in your Rhino? its like the manual…you can type in, say, “orient” and it will talk about tge command…with diagrams ans sometimes little video snippets…for orient, it would talk about orient 2 pts, orient 3 pts, etc…and maintain height…
julie
Oh yeah I have read the rhino command list back to front but I forget them 
. I never used orient before so that’s a fun new one. I’m on Rhino 6 so it could be new too. I used it as my main modeling software in Architecture school. Great program. I do wish there were parametric constraints like solidworks using variables sometimes.
Yes like Julie is saying, shoot a photo from the top side and end, import through picture frame one at at time and just draw a curve from each profile , in rhino 7 the tool is called picture and in matrix 8
it’s called picture frame, I always turn grid snap on so the photo and curves are consistent
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Hi
check out the “whats new” for rhino 7
i believe there were alot of additions, as well as potent subD
like how rhino 5 added tons of history functionality to commands…
might be worth an upgrade to rhino 8 before you get too far back and have to buy another full license…
also, no need to put a ruler in the scan…if you know what you want the stone length to be, you can just scale3d the stone portion of the image to the correct dimension in the program…i tend to put geometry down to snap to…curves…point objects…etc…i lean toward accuracy…thats why i ended up with Rhino/ Matrix
i tend to build from the center/ center gem outward…using the software to measure layouts…instead of trying to draw it to scale by hand…
julie
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Good points. Yeah I will definitely look at upgrading soon.
If using Blender import a photo of the stone taken straight down overhead and make it transparent. (Just drag the jpeg right into Blender)
You can then make a polygon with the shape and dimensions of the stone by extruding vertices. (Shift-A, add mesh, single vertex)
(Edit mode, E to extrude. F to close final gap)
Once you have an approximate 3d model of the stone you can use that to place prongs or extrude a bezel wall.