Offset surface in rhino


#1

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)


#2

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

Andy


#3

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


#4

I uploaded :slight_smile:


#5

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.


(David Cockey) #6

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.


#7

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:


#8

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…


(David Cockey) #9

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?


#10

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


#11

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.

Andy

octagonal_signet-2DC.3dm (686.2 KB)


#12

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

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


#13

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.

«Randy

octagonal_signet test-1.3dm (344.8 KB)