FreeCAD and Mesh Import

Post-Import
After import the model is (for FreeCAD), just an assembly of faces. You might want to convert the model into a shape FreeCAD can recognize and that could be altered in FreeCAD.

To do this:
 * 1) Switch to the [[Image:Workbench_Part.svg|24px]] Part Workbench
 * 2) Select the mesh, and go to the  or press the [[Image:Part_ShapeFromMesh.svg|24px]] Part ShapeFromMesh button
 * 3) Click  in the dialog
 * 4) Select the newly created shape
 * 5) Go to
 * 6) Select the newly created solid
 * 7) Go to  or press the [[Image:Part_RefineShape.svg|24px]] Part RefineShape button

Note: The last step is not necessary, but it will clean the solid of most of its residual edges on planar and cylindrical surfaces.

"cannot convert because shape is not a shell"
Well, your shell seems to have errors, maybe it is not closed (has holes). Since the capabilities of the mesh workbench in FreeCAD are a little limited at the moment, you might want to try examining and repairing of your model with third-party software. After doing that, you may try importing and converting of your model again.

Third Party Programs

 * Meshlab
 * License: Open Source (GPL V2)
 * Runs on Windows 32/64 bit, Linux and macOS
 * netFabb basic
 * License: Freeware
 * Runs on Windows XP/7/8, Linux and macOS

Tutorials

 * Import from STL or OBJ
 * Export to STL or OBJ

Related

 * FreeCAD Howto Import Export