Working on a bit of a small item here - it’s intended to be 3d printed as a game piece, so working at a larger scale doesn’t really help much. I have a dome of diameter about 1mm depicted as below:
Everything seems to be fine so far. The moment I click ‘save’, however, I suddenly have this:
You should work at a larger scale anyway. SU has difficulty interpreting very small dimensions. The accepted workaround is to scale up your work say by x100 or even x1000 and scale the result back down by the same ratio when you complete the task.