Closing a face when it keeps making tinier and tinier triangles?

I’ve been using SketchUp for years since ver. 1.0. I keep finding a rectangular opening that sometimes forms when I pushing or pulling a face. I try to close it with a rectangular and it doesn’t close, so I suppose that it’s not coplanar. So I draw a diagonal and get a filled triangle for one half, but the other half is still open. Then I divide that triangular shape with another diagonal and it creates another triangle with another open space. This continues almost ad infinitum with smaller and smaller triangles driving me nuts. Finally a tiny little triangle closes the space. This is important to me since many of these shapes are destined for 3D printing and have to be complete solids. What’s going on?

The opening appears in a face out of nowhere while push pulling that face? I don’t think so.

Push pull won’t even work unless it’s on a flat face to begin with. Whatever you’re doing it likely has to do with imprecise drawing. You’re only patching a mess. Instead you should redraw correctly to avoid this.

Upload your model if you want anyone to see what’s going on. And update your profile so people can help you better.

I’ve been trying to find an example, but of course one eludes me. Meanwhile, I have another more prosaic problem. I’m trying to go on the SU 3D Warehouse, but it’s not recognizing the password I have saved. So I attempt change password and put in the eMail address, but no eMail is appearing. Does anyone know what’s going on?

About your original problem, if you are creating faces by drawing lines, and one area is stubborn about filling in, look closely at the reluctant corner. There may be a gap.

For the password email issue, see if what I wrote here helps: