Thank you in advance for your help. I have an outer closed solid and an inner closed solid that is completely enclosed by the outer one. I want to subtract the inner solid from the outer solid, producing a single hollow solid with a cavity equal to the shape of the inner solid while preserving the o…

You can achieve what you want with merge breps from rhinocommon. There is command in rhino, and heres code in gh [image] Shelling a Shape Grasshopper I am not sure that is helpful here, but thought it was related. You can achieve void inside closed brep witho…

If you want to 3D print the object, the easy solution is to have a tiny hole connecting the outer and inner shape. I Rhino you can use _NonmanifoldMerge NonmanifoldMerge | Rhino 3-D modeling What do you need this for?

Thank you again for your reply. My main goal is to obtain the hollow shape so I can calculate its volume, moment of inertia, and other properties. I used a sphere to express the problem with a simple example; however, the main shape is more complicated.

In Grasshopper you will either have to subtract the inner volume from the outer volume or if you need the actual geometry you can convert to mesh and then the boolean difference works

Thank you, Martin. By using mesh, it works. May I know the logic behind this? I mean, to remove a specific mass from a larger volume where the inner body is completely inside the outer body: after generating the hull shape, it needs to become a mesh, then use “Mesh Difference”?

I cannot explain any better. Try yourself with NonmanifoldMerge and see what volume you get and compare with the mesh approach. [image] Amirhussein Montazeran: after generating the hull shape, it needs to become a mesh, then use “Mesh Difference”? Yes, convert the outer and inner shape to me…

Thank you so much for your help. Your proposed way really solved my problem.:slightly_smiling_face:

Perfect, then you can put solved flag on my answer

Just gotta be careful with the results of the volume evaluation… [image]

Solid difference

Grasshopper

dfytz1 July 12, 2026, 3:02pm 8

You can achieve what you want with merge breps from rhinocommon. There is command in rhino, and heres code in gh

'Solid Union' component

Topic		Replies	Views
Solid Difference to Make Hollow Sphere Grasshopper	12	4454	March 23, 2020
Solid difference--One solid(A) is inside another solid(B) Grasshopper windows	4	757	July 9, 2021
Solid difference fails where Rhino Boolean difference doesn't Grasshopper windows	5	255	April 18, 2025
Hollowing out insides of solids ..how is this best done? Rhino for Windows	17	37529	February 15, 2025
Boolean - which one is the same as AutoCAD Subtract? Rhino for Windows windows	11	1268	December 14, 2021

Solid difference

Related topics