@dave r said:
I guess I'm "nobody." Maybe others can see it. I do have Java but evidently it still wasn't happy.
Yes, checking for and getting rid of extraneous geometry should help but if the entire model is at some distance from the origin you may still get the clipping. It also seems to be more likely to appear in Parallel Projection which you didn't say anything about.
If you wanted you could send me the SKP file via PM and I'll take a look to see what's going on.
I've just selected everything and copy/pasted into a new file and it seems OK now. I still don't know what I'd done wrong, but thanks for the offer of help.