Ok, we were runnig a small experiment using _blocksize 0 in the worldspawn. My goal was to make a complex leaf node that kind of stretched outside of the map but you could still see it through the sky. I tested this idea with something far simpler outside loop and it worked fine but when i tried something complex it seemed not to. Because _blocksize is 0 and I have no portal lines being drawn whatsoever other than by structural brushes, there SHOULD be only one leaf node in this entire map. Because there is only one leaf node, players when standing in that leaf node should have a PVS set of one leaf node, and should be able to see the entire map. There are areas that extend out of view but they are covered in sky so they should be viewable.
Keep in mind there are no portal lines in this map other than the structural brushes themselves, and the entire map is connected as one piece, just a 50 sided room or so.
Here is an overview of the setup in radiant . If you look at the upper right picture there is small passageway connecting the main middle area to the outside halo.
Here is a another pic of the small passage way. It was enlarged a bit in this pic because i tried the compile over again but it did the same thing.
To my dismay, after compiling, there were portal lines??? why are they there? Here they are on the 2d grid
Here are the portal lines on the 3d grid
Here I am standing out in the outside halo with detail brushes filtered so you can see there shouldn't be any portal lines being placed in those hallways.
Here is one last picture. This one is me standing in game looking at the little passageway to the outer halo that should be connecting the entire thing as one solid leaf node. Instead you only see a small section of the halo, and it stops in accordance to the random portal lines that the compiler inserted with telling the compiler to insert (as seen above.)
So we have no hints, no subtle hints, no blocksize automatic lines being drawn, no area portals or anything, but we're still getting portal lines drawn in by the compiler.
Why is that and is there anyway to stop the compiler from doing that?