OK, this happens to me once in a while,
but, I forgot how to fix it.

It's the front of that one rectangular section.
Why does it not render or fill like all the others.
I have tried flipping, re-finding normals and those are all single cp's.
I have moved and checked them all.

I guess I could tessellate that front box, if I have to, but shouldn't it just fill like the others near it ?

my first guess is that that four-sided area is really one spline. By design, a one-spline loop will not fill in.

Hmmmm... OK, i'll re-work it and see what I can get, thanks

OK, re-did it and is OK now.. thanx