.IGES maybe work.
Hi, I’m a trainer for the last 10 years on Rhino.
We live in a tiny village. There I’ve a teaching institution for poor and needy people.
I know the solution. I’ve a software that can accurately convert jcad files (.jcd) directly in to rhino file (.3dm). After that you know all that it is easy to edit place gems, easy to make it STL or anything can be done by rhino!!!
Contact me for more information and pricing. I can make some profit too from the seller.
I’m glad that I’m able to help you guys honestly. It was really a painful talk earlier, slicing surfaces in jcad, exporting, put it in Materialise Magics etc etc! Now we are good to go! No limitations!
Contact information:
+91 8944936629 (WhatsApp)
cadjewelryacademy@gmail.com
Thank you 
Oh yes I forgot, this software have all the features what jcad have already. It actually made for the jcad users. So you can create jcad files from thino 3dm files too!
You can place gems, prongs, textures everything! You can say it is an alternative to Matrix but in a lot cheaper price!
Thanks again guys for your attention!
The above can now quite easily be fixed with ShrinkWrap in Rhino 8
1 Like
Not possible! 
I’m not sure what you are referring to, but I was referring to this type of open geometry, that can now be fixed with ShrinkWrap:
1 Like
Can you please make a video and upload?
@CAD_Jewelry_Academy have you seen this:
1 Like
Yes I understand what are you trying to say! but it reduces the polygon counts, also reduce the quality. Have you ever tried to convert a jcad file or are you just experimenting ShrinkWrap on a pre made rhino STL file?
Because what I saw on your model, that is totally a normal STL. It is not an exported STL from JCAD. Exported JCAD stl is different, totally different. JCAD can’t even make a good STL, it make STL files like a slc file but again it is solid! Looks totally different. It looks like step by step sliced metal body, not smooth! ShrinkWrap is not useful for that type of STL files. You should try! I challenge you, if you make the file smoother, the file size will be over 1 GB. 
Please try. Make it smooth.
It could be done with a plugin only. It can make JCAD file in to real nurbs
The NURBS exporter sounds pretty cool.
However in terms of other ways to export directly to Rhino 8, you shouldn’t export the STL from JewelCAD as they are pretty worthless as you mention. You should export SLC. The SLC will come into Rhino as curves. Next extract the points of the slice curves and ShrinkWrap the points as a Point Cloud. This solves the stair stepping issue you’re describing. Here’s an example of a JewelCAD exported as SLC then ShrinkWrapped.
You can find the SLC example on the page that Gijis referenced above.