Make stl into solid and smooth surface

[Valentina_Mejia_Gall (Valentina Mejia Gallon)]

Hello Andras,
I have a question, searching in the forum I came across this article about how to save and convert the vkt file into a volumetric mesh, but I don’t know how to manipulate 3dSlicer with code.
Is there a program or a tutorial on how to do that process?

Article

Convert a surface mesh to a volumetric mesh in 3D Slicer

ICEM can import surface meshes (STL files) - see for example this old forum topic. Segment Mesher can generate tetrahedral meshes that you can save in VTK unstructured grid (.vtu) file format. You may need a mesh conversion utility to convert it to a file format that can be read by your FEM software.