Since airports are built on flattened ground, couldn't every item...a runway for example, simply be made by creating and placing it accurately as a large very thin GMAX 3D polygon?I can only assume the simulator might see "through" the very thin polygon to the ground below due to video card or other problems.:-walksmile

Yes, indeed, it's possible. You just have to edit the source a bit. "If you use GMax to draw ground polygons you will notice that they will often flicker and you will see the mesh texture through it, also you don't see the shadow of you aircraft on them.This is because the code GMax makes is meant for 3D objects and not for ground objects. To change this you can make the following changes to the BGLC code.Find this piece of code in the asm file of your object: OBJECT_0_START label wordIFIN1 OBJECT_0_FAIL, image_complex, 2, 32767ADDOBJ OBJECT_0_SCALESHADOW_CALL OBJECT_0_SCALEOBJECT_0_FAIL label BGLCODE And replace it with this: OBJECT_0_START label wordIFIN1 OBJECT_0_FAIL, image_complex, 2, 32767ADDCAT OBJECT_0_SCALE, 8OBJECT_0_FAIL label BGLCODE The parameter 8 is the layer number. Make sure that number is always higher then the layer number of the polygon you want you polygon to show on top of."More tips -> http://home.wanadoo.nl/arno.gerretsen/PS. Export ground polys as separate files from other objects or You'll see some strange effects.

That text looks familiar :D.So it is possible to make a ground polygon with GMax (no need to place it a few cm above the ground or so). But when you place a lot of polygons in one GMax file the performance doesn't seem to be that good. This is because GMax puts everything in one RefPoint with one v1 and v2 value. While other design programs give each polygon their own RefPoint and that gives a better performance for a big airport.