Using an offsetsrf extruded curve to engrave not working

I’m trying to engrave the face of a signet using an SVG imported from Adobe Illustrator which I extruded and offset to give thickness. When I attempt to boolean difference the imported curve and the signet face, it always fails. I’ve messed around with different offset thicknesses but it’s not working no matter what I do. Any help would be greatly appreciated!

'Whale Signet.3dm (3.7 MB) Whale Signet.3dm (3.7 MB)

Are both of the objects to be booleaned closed solid polysurfaces when you select one and then the other and check the properties of each?

They’re showing as open polysurfaces, is that a problem?

Hello - looks pretty messy -


Plus, when it is all cleaned up, the cutter will need to fully intersect the target object. Very often curves from AI etc. are ok to show on screen or print but not very good for creating clean surfaces - I have not looked closely yet at your curves, but I’d try to clean them up as much as possible.


Thank you for your reply! How would I go about cleaning those curves up?

Maybe I should import the AI file as a PNG and try to trace over it in Rhino to get a more useful curve?

Hello - the curves are not terrible - see the attached file - I offset them to both sides and created clean closed curves - extruded these into a single solid, which will BooleanDifference nicely from the ring.

Whale Signet_Maybe.3dm (853.3 KB)


I’m not at my Rhino machine right now so can’t take a look at your files. I believe that your ring will need to be a closed solid also.

That works!! Thank you so much you’re a life saver. In future when I’m doing something like this, do you mind giving me a little step by step? Whenever I try to extrude a curve it ends up as a sort of super thin surface that gets all wonky when I try and offsetsrf it. Thanks again!

Hello - did you see that I built the curves from your originals as offsets (Offset command), cleaned up at the corners, and joined into clean, into closed curves?


Yes I did see that, it ended up working great. Just curious as to how you join an offset to the original curve?