Using free demo model to try out the program. After building a model along with a tutorial, everything working fine, I save it. Thereafter, first time I zoom, it goes blank. It looks like it is going to infinite (max) zoom, as there is some small detail, but cannot retreat the zoom, rotate, or effect any more commands. Tried save as, logging out and back in, redrawing from the beginning, always the same result. I can draw, but as soon as I save it, the program freaks out.
Upload your model so we can see what you’ve got. I expect it’ll be fixable.