Imported SW file into rhino, issue with internal

So when i have a part for 3D printing where the shell is closed (inner cavity.)

ive exported a couple ways, goal is to import into Rhino, edit surfaces more, and export as STL with inner cavity (shell)
but all surface files types import it as 2 parts, or blockm and then the exported stl is not a cavity, but two bodies within eachother.
How do i import a shelled body into rhino and keep it as one?
or how do i export its as a shelled body?

Hello - if you Mesh the objects and flip the inner mesh direction inward (Flip command) then Join the two, the result will be a single disjoint mesh - export that to the printer - I guess that will work. However… what will you get from this? If the inside is hollow, support material will just sit in the cavity for ever… and if you are going to open it, why not split it before printing? If the idea is to save on material, I think most printers can make a lattice interior for thick sections.
What is the goal here?



I’m totally aware of the support material stuck in there.
that is part of the goal and its particular to this print material and project.
your method did help (flip on inner body and exported to stl)
re imported result and clipping plane shows it like a closed body inner cavity.

issue is, ive got a body with 200 unique cavities within it, and flipping each or making sure each is correct seems daunting. ill do it if i must.
but would be great to know if its somewhere in the import of a SW or IGES/STEP solid bodies, Rhino can keep them as that one Body, for editing and exporting it again as one body (with the cavities)

like in SW if you cut inside cavity, its still one solid body.
but in Rhino, it only cuts inside cavity if the parts intersect

_NonManifoldMerge followed by _CreateRegions on your hollow objects will make “disjoint” hollow polysurfaces. The problem is that _CreateRegions will also make the inner region separately - i.e. for each hollow object you will have the outer shell and the inner enclosed volume, which you will need to delete for all the objects you have. You can probably find those objects with a combination of the selection filter set to polysurfaces and using SelSmall with some value larger than the inside objects’ bounding box diagonal. Otherwise a script.

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Oh wow, these are all new commands to me, ill explore!

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