STL 3dit
An STL model viewer, editor, and creator for manipulating STL files.
This software allows a person to open, edit, create, modify, view, and save 3D STL models. It can also be used to extrude 2D images into 3D objects. You can also insert 3D closed primitives.
The new STLX file format supports groups, materials, as wells as colors and generates much smaller files on average (compared to binary STL files).
NOTE: This latest build targets only 64-bit Windows Operating Systems due to the necessity of being able to manage (and navigate) very large 3D models...