I don’t use define ground plane…
If you want to have consistent outputs. so the models all line up each time you export. you need to setup up proper co-ordinates.
I set both project and output co-ordinates systems. to the real-world co-ordinates based off UTM. I then manually add the x,y offset to move the model back near zero. I’ll save this number somewhere else and re-use it each time i want to export a new model.
works much better to get files in and out of rc consistently.