I have the following:
I'm trying to dissolve all of those edges so that face is unbroken, but when I select all of them and use Delete > Dissolve Edges, I get the 'Invalid boundary region to join faces' error.
If I dissolve them one at a time, it works, and I can get it down to two edges, like here:
But then those two get that error when I try to dissolve them both individually and at the same time.
How can I get rid of these edges and make this face smooth? This model is intended to be 3d printed eventually.