There's just no way to convert the scenery for FSX, even us couldn't do it, and we have all the source files:
- FSX objects cannot have more than 64K-vertices per Draw Call, due to the usage of 16 bit pointers for vertex indexes. The P3D .MDL format doesn't have this limitation, having 32 bit pointers, so P3D native objects can theoretically have up to 2-billions polygons. We obviously took advantage of this, because it's more efficient to draw, let's say, a single 256K polygons object in a single Draw Call, than having to split it into 4 separate Draw Calls, since every unnecessary draw call slows down the fps.
- The materials are all PBR, and they were made with *proper* PBR materials, not conversion from legacy textures, and they don't look very good if "converted" to the non-PBR specular/diffuse model.
- We made heavy use of the 2nd UV channel, to add extra details, baked Ambient Occlusion, dirt on ground, color variations of the concrete aprons, and FSX doesn't support this so, even if you could just ignore it the 2nd UV channel, the scenery would look bad without it, very flat and FS9-ish. That's the brave new world of PBR, were individual textures (Albedo, Metallic, AO, Detail, etc.) look "flat" if seen stand-alone, but when used with a PBR Shader, all the magic happens...
- We used our special DirectX rendering for lots of the more interesting stuff, like active information panels that shows the flight information for your airplane and AI planes as well. They are a very distinct feature of O'Hare, and it wouldn't look very good without them. Of course, this technique is only possible with the P3D4 SDK, since FSX simply doesn't have that feature.
- We use GSX L2 SODE Jetways, which allows (with the aforementioned DirectX rendering), to have all Gate Numbers on jetways, with their proper color and fonts, with a minimal impact on fps. FSX doesn't support his as well.
- We used the native P3D4 SDK to create multiple ground layers, without having to worry about flickering, and without having to play tricks with software to prevent it, like we had to do in KMEM or KCLT in FSX, which explains why they work so much better in P3D. KORD V2 will be even more reliant on this.
