I put on YouTube a short video of how to do a Batch Conversion from Rocksimm RKT to OpenRocket ORK Format. Why? Two reason, I don't have Rocksimm's program, have OpenRockets', secondly one can find a lot of rkt files and rather than opening one at a time into OpenRocket and then do a Saving As, I simply use this batch process to do the work and it works great.
This video shows using the F Drive on my computer, you use whatever drive is available to you:
Start off by making a folder named OpenRocket
Then in that folder make two(2) sub-folders named as:
Download and place the OpenRocket application file into the folder named OpenRocket
Download all of the Rocksimm (*.RKT) files your little heart wants into the sub-folder named RKT.
Go to the the Windows Command Promt and type:
cd f: (then press the Enter key)
Then will need to change directory or folder where the OpenRocket application file is located. As is in this example, it would be:
cd f:\openrocket (then press the Enter key)
Then type at the prompt the following line text:
java -cp OpenRocket-12.03.jar net.sf.openrocket.utils.RocksimConverter F:\OpenRocket\RKT\*.rkt (then press the Enter key)
This will then convert all of your *.rkt files into *.ork files.
Now simply select all of the *.ork files and move them to the ORK sub-folder. Or you can leave them there, but you will need to delete the *.rkt files for if you download any more rkt files and run the batch conversion process again, one will have the old rkt files converted again. This is why I move my files and then delete the rkt files.
Note if your Open Rocket application and sub-folder are different, then you will need to make change in the above commands.
YouTube Video link: