Both the C3 and GET file types can be found as graphics from POV-Ray software and as such this program is probably your best choice if you wanna save one to another. As far as we know, no other program is capable of this direct conversion.
Convert Pov-Ray for Windows 3.1 scenes advanced newltpot file to Pov-Ray 3D graphics.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert c3 to get on Windows
A free 3D graphics tool
Convert from c3 file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.