COPASI is one modeling and simulation tool among many and often people use more than one tool to create, investigate and simulate their models. In order to make it easier to exchange model files with other programs, COPASI supports reading and writing of several model file formats. Naturally COPASI can read and write it's own file format and it can read Gepasi files just as well although it will not write Gepasi files.
In addition to those two file formats, COPASI can import SBML files, SED-ML files and COMBINE Archives, it can export models as SBML , SED-ML, COMBINE Archives as well as C source code, XPPaut, or Berkeley Madonna files.
