3D Design Software and STL File Manipulation Software

 

3D Design Software

Software License Experience Level Website
Autodesk 123D Freeware Beginner http://www.123dapp.com/
OpenSCAD GNU GPL Amateur http://www.openscad.org/
FreeCAD GNU LGPL Amateur http://freecadweb.org/
Seamless3D MIT Intermediate http://www.seamless3d.com/
Google Sketchup Freemium Intermediate http://www.sketchup.com/
SolidWorks Commercial Expert http://www.solidworks.com/
Blender GNU GPL Expert https://www.blender.org/
Rhino3D Commercial Expert https://www.rhino3d.com/

 

STL File Manipulation Software

Software License Capabilities Website
Netfabb basic (free) Freeware Fill missing triangles, flip inverted triangles, and more http://www.netfabb.com
Slic3r (free) Freeware Capable of splitting a STL assembly into multiple STLs, merge STLs together, and create build plates http://slic3r.org
Materialise Magics Commercial A combination of Netfabb and Slic3r http://software.materialise.com/magics
Autodesk Meshmixer Freeware Use it to import stl files and manipulate them. You can split parts, add joints, merge parts, and add shapes to parts (like cubes, spheres, weird features) http://www.meshmixer.com/
Slash 3D Freeware Import STL models and hack away at them like Minecraft, or make blocked things from scratch and download as an STL. https://www.3dslash.net/index.php