What is it you are trying to do as in convert files. If you are talking rocksim then Openrocket will open them. If you are talking about adding thrustcurve files. You would need to open the file... A way to do this without cost... get 7-zip. It is free and will open the file. Install 7-zip. Right click on openrocket and select open with 7-zip. Drag the thrustcurve engine files into the datafiles/thrustcurves directory of the file. close/save and you are done.

Thanks Mitch,
I'll give that a try. Yeah, tring to add new files from thrust curve.

I must be doing something wrong? No, save option. I closed and tried no Joy. pretty sure i followed instruction. any other hints?

ok, I just tried it on my end. Here is what I just did. Right click on the Openrocket-1.1.4.jar or whatever version you are using. click on 7-zip, open archive. click on down to the datafilesthrustcurves directory. You should see a lot of .eng and .rse files. drag the file you are needing to add into that directory. If you scroll down you should see the file you just added. close the file by just exiting out. Your new engine file should be in there. to verify you can just go back in with the above steps and see the file you put in there.

Thanks Mitch,
I had to get the newer version for it to work.
Thanks again for taking the time to help me.

Welcome,
Pretty much we are all here to help each other.