I once had a platform, sth like 768-1024 quants long (player height = 90 quants), where the player could fall through the right 3rd of the entity, until jcl explained to me that I would have to adjust the bounding box (i.e. call c_setminmax) of the entity too.
So basically what I was trying to achieve with my workaround...
You're mixing up two concepts. An entity always has a bounding box - regardless of the POLYGON flag. This bounding box is determined by the min_x ... max_z members. The POLYGON flag just tells the engine to ignore the bounding box when doing collision detection, but does not remove it.
Aaah. Concept understood, thanks. All right, then just to learn: How does the engine compute th BB? Those in the pic (and others) are way off in their dimensions.