How can i convert the catia files into .3dm .stl .prt etc files ?
I think you have both catia and solidworks with you.
Save the files in .cgr or .igs format using your own catia.
Then open it in solidworks and save it to desired format using save as button..........
Answered with a tutorial: https://grabcad.com/tutorials/how-can-i-convert-the-catia-files-into-3dm-stl-prt-etc-files
You Can Simply Use Save as Option instead of only save option.
After entering the save as option you will find lots of formats like iges, step etc