Many users falsely think that for rendering the polygons, every polygon has to be calculated whom occur in a model. However A5/6 actually only render the visible ones. Backface polygons of one entity are'nt renderd. However solid polygons, which lie behind others (e.g.: of 2 different entities) are rendered nevertheless. Because of this you become in the worst case the polygoncount of your basis model for outlining plus the base model. If you use e.g. 200 polygons for your house you maximally get 200 rendered polygons for outlining AND rendering. Since we speak here of level architecture you can even save polygons when the bsptree deletes unseen polygons of blocks of your house. In addition you can save additionally polygonrendering if you mark all block surfaces as render = none, which are not to be seen. In fact you should not experience large performance break-downs if you already have a mid-polygoncount on average machines.

I hope this helps.

Good night to everyone
Christian Behrenberg