I think I might just have deciphered the new version 3 flatten command for FS9. There are 2 new features that could indicate that sloping runways are possible in FS9!I found that each polygon entry starts with 2 rather than just 1 height values. And each point now has a 3rd component that mostly seems to be set to zero (still have to find non-zero values). However, this may indicate a xyz point and could possibly mean that points can be set to different heights. This would obviously mean that sloping runways are possible in FS9.Still have to confirm this though...Christian

Hi Christian and others:I just found out (not sure whether I'm first or last?!?) that lakes can have a sloping surface in FS2004, and I'm not talking mesh clinging.While trying to measure a suitable elevation for lake flattens in the Revelstoke, B.C. area (CYRV, the default FS9 lake elevation is completely off) I discovered that some sections of the Arrow Lakes have gently sloping surfaces over many kilometers whereas others are completely flat.Try this: start a flight at CYRV, switch to slew mode and climb above the wall of water, place your A/C on the lake's surface (F1) and slew north or south, while watching the elevation display (Crtl-Z).The small water steps along cell or area boundaries, typical for FS2002, have disappeared for the most part and seem to have been replaced by sloping surfaces in suitable areas. I'm sure the HP9*.bgl were compiled with the help of some automated procedure. In the case of Revelstoke this didn't work as intended as there's a big dam just north of town, which made the algorithm compute a steep slope that ended up surrounding the airport with water.Christian, I assume this is related to your finding about the flatten command and probably is one reason why BGLAnalyzer doesn't work with FS9 HP9*.bgl files.Cheers, Holger