How to fill custom cavity in 3d model?

hello guys, please help a newbie out!
i have a cool figuring that i want to print, but it was made hollow to save plastic & time); now i want to make stl model that has no cavities, i.e. is completely solid, cause i want to cut it in half and add changes to its insides! sorry for my terminology, i have no bg in modelling what so ever…
tanks a lot! have a good day!

Does the ExtractMeshPart command and clicking on the exterior of the figurine do what you want? From your description it sounds like there is an interior wall but it’s not physically connected with the exterior. This command should separate the inner and outer shells. Saving the exterior as it’s own stl should print as a solid but the printer settings will determine the fill density.

i can’t click on exterior - have to select gazilion triangles; when i select all this command literally does nothing

Hi Eugene- try Weld on the mesh, at say 30 degrees, or whatever looks right in the preview. Then ExtractMeshPart. Better to post the model.


here is the model
Grip_with_peg__Hollow_.stl (458.5 KB)

when i try to weld, it keeps asking me for degree forever…

Hi Eugene - try CutPlane through the center in Top - use the Vertex OSnap to start the plane right on the center vertex on the left (in Top view). Then MeshSplit using the plane as the cutter. Not sure what you want to do from there.


thanks! i can cut it in halves, but its making halves solid thats beyond me; as you can see - they have cavities, and i simply want to have a solid piece of plastic…

Ah, OK - then, starting with the original mesh and the cut plane, use MeshBooleanSplit with the plane as the cutter.


done that, no luck!

have still have 2 empty halves, what am i doing wrong?

Hi Eugene- reread my post above- did you use MeshBooleanSplit on the original unsplit mesh?


Hi @Eugene_N

Is this what you are looking for? I deleted the internal cavity (DeleteMeshFaces on the first row - both top and bottom - of polygons inside the cavity and the SplitDisjointMesh to separate the rest of the cavity) and used fillmeshhole to fill the resulting gaps. And then MeshBooleanSplit to split it in half.

Grip_with_peg__Hollow_JNN.3dm (452.9 KB)

HTH, Jakob

Normand, you are great! thanks for explanation and help!