Offset surface in rhino

Hi there,

I have made an octagonal signet ring what I need to offset in order to have 1mm thickness to cast. So far I tried to offset inwards, then someone recommended to try offsetting outwards… it still doesn’t work…
Any suggestion? (It has to be a ‘see through’ ring)

I do, but can you post the file to test?


yes, I can!
octagonal_signet.3dm (260.2 KB)

I uploaded :slight_smile:

From your file I do not see what you want offset. Is a stone supposed to go in the top flat area, open like in your image?

Your ring is closed right now.

OffsetSrf works for me. Attached file has surfaces offset to the interior of 1 mm and 0.1 mm, and surface offset to exterior of 1 mm. octagonal_signet_DC.3dm (1017.4 KB)

The interior 1 mm offset region is small because most of the ring is less than 2 mm thick.

yeah, sorry, if u explode and remove the inside ringshank and the top, then we have the base ring… I tried to offset, see on the pic what happens… then I got an advice, to copy the ring, scale it and boilean difference them, but it didnt work either… :confused:

I did offset it inwards… u have to be able to see the thickness of the ring, as it’s an ‘open/see-through’ ring… but the octagonal form is not nice when I offset…

It appears you have an offset surface so something worked.

Does “it didnt work” mean it did not give the result you wanted? If so what do you want?

let me show another example (-that’s what I want)

It’s easier to offset inward, if you rebuild the ring a little. i’ve done a very quick example - the surfaces aren’t great but it’s quick. (I say easier - I mean it was easier to offset inwards in this instance with the shape you’re looking for - if you already have the outer shape you want. If you want to offset outward you’ll have to do a little more rebuilding and messing around)

I basically duplicated the borders of your surfaces and swept with 2 rails to remake the ring without the split in the middle (at the bottom)

It was done as a single surface then I duplicated the border on the top face and copied, scaled and then lofted.

It might be a good idea if you redraw the basic geometry with circles and lines tangent then try extruding and lofting again.


octagonal_signet-2DC.3dm (686.2 KB)

Apologies, the first version was cosmetic - this one is more uniform:

octagonal_signet-2DC_ Rev_A.3dm (936.9 KB)

Lots of ideas here, If you want a flat top. I would duplicate face border of your top shape and offset that curve. Then extrude and then trim.

Offset will always offset Normal to the original surface.


octagonal_signet test-1.3dm (344.8 KB)

octagonal_signet_Alias.3dm (286.1 KB)