One surface of a block is invisible when I run the game. I don't get any error messages on that block while building, only a plane too narrow and vertex out of plane on some other blocks. Any ideas?

The highlighted face isn't visible. This was first one block, I did a subtract in the far corner, and an edge move to get the angle of the bottom face.

Ok, I duplicated it, moved it a bit, and it's visible. I guess I'll have to experiment a bit like that whenever something disappears for no apparent reason.

I suggest you use models for this job...I dunno why this happends but try to make a detailed cave from blocks , you will see in-game that half of it is missing (if you dont get any errors...)

Yeah, I've noticed people mentioning this. Whish I had known sooner... too late to change approach now, I don't have time to learn a lot of new stuff as deadline is saturday morning.

Anyone got any hints for dealing with this? Sometimes it works to just move stuff a bit, but not always. I see no logic to this. :/