Create a base to an open mesh to make it closed

Hi all,

I have an open mesh, and want to make it a closed mesh so that I can then obtain the volume and do some subtraction/difference exercises with it. I can’t seem to get a closed mesh though.

I have tried several things. The process I thought would work would be to extract the outer edges of the mesh, project these to the world XY, loft between the two polylines and then join all meshes together, but it doesn’t
seem to connect and I am left with open meshes still.

Any thoughts?

190427_solid base to (14.0 KB)

Here’s two ways, top native gh, bottom needs Weaverbird and Mesh Tools. (both use Pufferfish just to test if the mesh is closed). (14.2 KB)

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190427_solid base to (11.8 KB)

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Perfect, thanks guys! The native gh way in @Michael_Pryor 's script is fairly similar to what I had been trying, I guess the naked edges was what I was missing.

Ok, so I was able to use the above to make a solid base and then subtract an extrusion from it to get a new volume, and it worked fine with all meshes being closed. However, I then made a slight tweak to adjust the overall depth of the base, and now when I remove the volume it results in the final output being an open mesh!! When I bake the output it appears to have chopped a corner off for some unknown reason, any ideas as to why this could be happening?

190428_mesh closed to (29.8 KB)


I had a quick look and I am not really sure. The weird thing is the solid union of the brep actually results in an open brep, however when you mesh it it becomes a closed mesh. I baked both brep and mesh in rhino and the same occurs, Rhino says the brep is open but the mesh version is closed. Whatever the cause is there I suspect it is the issue, could be some tolerance issue somewhere.

You can join meshes after difference

190428_mesh closed to (21.8 KB)

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