Self Intersecting Input Error with Splitting Tool

[oi3WS5F]

Hi World - I have an issue that I can't understand:  when trying to split a body, I get an error message saying "avoid self-intersecting inputs" which I've never gotten before on identical models...  The same result is happening on other models, all since F360 changed their rules... Any connection?

[oi3WS5F · Accepted solution]

Ah never mind! I discovered that if I created an angled plane, it splits properly.