Disappearing faces

Got a problem where some brushes I have made in Netradiant then "disappear" in Xonotic, flickering back as you move around.

   

   

Here is the .map and .bsp file. The stuff at the bottom of the well where it happens is supposed to be rubble where the floors have collapsed. (I'm rubbish at art in general so excuse the crudeness of the thing)


  maps.zip (Size: 34.77 KB / Downloads: 3)

Thanks for looking.

Quick fix for this problem:
Make the brushes which are rotated and don´t match the grid detail brushes by selecting them and pressing Ctrl + M.

What are "detail brushes"?
There are two types of brushes (/blocks, those things you build in Radiant): structural and detail brushes. By default, all brushes you create are structural. They create VIS portals which enhance the performance of your map by hiding not visible parts of your map. You can toggle portals for debugging issues in NetRadiant on and off in the Plugins menu (Plugins -> prtview -> Load .prt file):

You see that the generated portals are a hell lot of a mess. Now, making the special brushes detail (marked red in the following picture) it becomes quite nice:


What are VIS portals?
Please read these articles:
Understanding Vis and Hint Brushes
Detailing the BSP VIS process

Other improvements
Please make your way through this tutorial: http://en.wikibooks.org/wiki/GtkRadiant/...GtkRadiant

Thanks for this Maddin. I deleted them and worked out they were the problem but until you told me, didn't understand why. Am reading the links you have supplied.