It may greatly help me find the bug if you send me your rocket file with the lathe that you are unable to progress from.
To be sure you do not loose all your work, as stated in the survival guide, make lots of backups. To be sure your backup files are uncorrupted, close seamless down and then open them in seamless but do NOT save them after checking they are OK. It is impossible for seamless to corrupt a backup file if you do NOT thereafter save it with seamless.
The files you sent me were saved with 3.007. I know these files are working fine but before reporting a bug please make sure you're using the latest version as it can be very unproductive for me to test for bugs from out dated versions.
It does not help me much to isolate a bug if you do not specify which instructions you are following. I have no tutorials for Seamless3d 3 showing how to make the models you have sent me, they are your experimental work. There is nothing wrong with experimenting outside of my tutorials but the more you go outside what is documented, the less you can expect things to work. This is why it is important for me to write more seamless3d 3 tutorials as this will help document what exactly seamless3d 3 is capable of.
I tried adding lathes and RectangleBuild nodes and had no problem converting the rectangles to patches and opening the files after saving them, however I am aware that there has been problems with seamless3d 3 (at least with earlier versions of it) using a combination of stitched patches and non converted build nodes. Since I generally convert everything to patches (all of my focus has been on making models using nurbs patches for seamless3d 3 so far), I avoid saving files with a combination of non converted nodes and stitched patches and so the practice of saving files with a combination is not yet well tested for Seamless3d 3
PS I have fixed a bug that arises when converting a non mirror BoxBuild (not to be confused with a RectangleBuild) node to stitched patches for the upcoming version.
PS The Seamless3d chat server is not currently running. I found a bug that caused a crash when opening techuelife island. I will run the server again after uploading 3.011 which has the bug fixed.
Best wishes