Once an STL file has been converted to a solid model, you can use the entire SolidWorks modeling toolset to edit and modify it. With such well-thought-out features, the program is ranked as one of the best 3D sculpting software. The 'STL Edit' command in this software allows you to directly modify the geometry of an STL file, and the '3DPRINT' command is used for preparing STLs for 3D printing by error checking and geometry optimization. You can also use the 'TRIM' or 'FILLET' commands to change the geometry of the STL file as needed.
In AutoCAD, you can use the 'EXTRUDE' or 'REVOLVE' commands to create 3D solids based on the geometry of an STL file.