GibbsCAM uses the Gen 3 solids toolpath engine. The Gen 3 engine provides many improvements over Gen 2, including smoother and more optimized toolpath for contouring operations. Gen 3 is optimized to produce toolpath consisting of lines and arcs.
If you open a part that was created in an older version or if a part needs to be saved to an earlier version, the Gen 3 Engine automatically converts toolpath to or from older versions of the system.
Older to new version
Data imported from earlier versions of the system does not have all of the functionality of the Gen 3 engine and the new features. To accommodate this, the process is rebuilt with whatever data can be gathered from the old process and the new options use default values.
New file being saved to an older version
When saving to an earlier version, all of the new functionality is lost, but valid toolpath is still generated. Saving back to versions 5.1 through 6.1 uses Gen 2 and even Gen 1, where appropriate. Saving back to versions prior to 5.1 uses the Gen 1 engine exclusively. Saving a file to prior versions does not result in identical toolpath, but the toolpath is valid.