Adjusting thickness on hollow organic sub d sphere

Rhino SubD
, ,
1

Hello, I am making an organic hollow sphere-like shape, I created it in grasshopper and subd modeling, now i must adjust the thickness of the walls to 1.2mm and am wondering if there is an easy way to do this besides using a clipping plane and manually adjusting. I am pretty new to grasshopper…

I have tried

  1. removing all inner faces and doing an offset sub d but the results are a bit strange.

  2. converting to nurbs and shelling but it is unable as the faces wrap around.

  3. I have also tried converting to polysurface and boolean difference with a smaller copy but kept getting surface intersection error.

I have include the file.Thanks again guys I am at a loss

organic sphere
organic sphere807×679 83.9 KB

organic sphere.3dm (431.0 KB)

2

Is this for 3D printing?

Shrinkwrap with negative offset and the subtract it from a mesh of your SubD…

3

yes it is for printing, i tried doing a -1.2 offset on shrinkwrap of a regular shrinkwrap but i only get tiny pieces of the model, am I doing it wrong?

4

Your object has a self intersection at the top. It’s not just the subd itself but also the edge looks not correct.

image
image1473×1341 106 KB

image
image1244×880 53 KB

Shrinkwrap can be used to fix this and then create the shelling.

The object itself is not very thick and you indeed get multiple small bits and pieces, already at an offset of -0.5

image
image1809×1267 213 KB

image
image1291×1185 66.4 KB

organic sphere.3dm (5.4 MB)

1 Like
5

thanks, i have fixed the top part since posting, but getting bits seems inevitable, i guess i will have to adjust by hand with a clipping plane, thank you

6

What is the expected benefit of the shelling?

7

it will be cast in gold, so it´s more about product cost, but i have managed to get the volume down to a acceptable number, thank you for your help

8

it will be cast in gold, so it´s more about product cost, but i have managed to get the volume down to a acceptable number

9

I am curious …
If it is an investment casting how would you create the core so you get a wall thickness rather than a solid, or are you casting it in sections and assembling it?

1 Like
10

yes casting it split in half with a plaster mold. Cast in half for finishing purposes then sodered together to assemble