I have noticed that some quite complex add-on sceneries are quite OK in the FPS department -- but some others, which may even be only quite small renditions of an airfield, absolutely kill my FPS. It makes it so that there is not much point in installing addon sceneries because you don't know which ones these will be. Is there something that I should be looking out for here? Size of download file, etc?Regards Barry

It has to do with the developers and techniques, GMAX or not etc etc.People like FlyTampa and FlightScenery have it down to an absolute art in making the most beautful and complex scenery there is without making a hit or your FPS. Infact sometimes improving it; others just cant do it. Imagine Simulation I like the scenery I use it and it gets acceptable fps but makes a definite hit because he just doenst have the techniques that the other guys have. SimFlyers older stuff kills your system but PHX and LAS are wonderful in the FPS department.

The most significant impact is the number of polygons to be rendered.Scenery, just like AI aircraft, needs to be built with multiple LOD - Levels of Detail.FS also does not "hide" polyogns very well. It does not know that you cannot see the very complex scenery on the inside of a building - it draws and textures the interior, then places an exterior texture over the top to cover it up. All the while eating up your graphics performance.If you want a really detailed scenery - look for some indication that the modeler has written mulitple much less detailed models into the scenery - for viewing a farther distances.Be very wary of open ladder like structures with a visible external frame work. Be wary of interiors.For example - hanger with four sides and two roof sections can be just 14 polygons (all polygons in FS are triangles - a rectangle will be split into two triangles). But polygons are one sided - to add an interior to the hanger visible through an open door - or visible if your aircraft is inside - requires 28 polygons - a 100% increase in processing to display the image - even if you are on the back side of the hanger and can only see one polygon.Also - some texture painters are very good at creating a 3D like effect with shading textures. Very good modelers and texture painters never create a 3D effect on a model - when a texture can create the same effect.Those are just the hi-lights. There is a lot more - but in general - the older scenery, the less likely it is to take advantage of the newest FPS friendly techniques.

Ah, very informative Reggiie. I just switched back from JC McCormick's KFLL 1.1 to 1.0 for this reason - I get as bad as 6fps on approach with settings up high where I like them.Interestingly, and to I guess illustrate what you're saying, when parked on the ground and rotating around my a/c in spot - i get 25 - 30 fps till the main terminal is in view - drops to 12.1.1 is nice but my rig can't handle it at very dense plus lots of AI - no problem at other big airports though.regards,Markhttp://i14.photobucket.com/albums/a319/markrey/lds1.jpgXPHomeSP2/FS9.1/3.2HT/1GIG/X700pro256