Using Glass Objects in Planes

X-Plane 9 allows you to categorize objects as being on the plane's outside, inside, or glass. X-Plane depends on these flags being right for a few things:

• The draw order of the airplane is determined by the object types - glass is drawn last to avoid translucency artifacts.
• Interior light from the plane is only spilled on the "inside" objects.
• Glass objects are excluded from shadow calculations to avoid having opaque windows in the airplane shadow.

It is important that you use these flags as intended; X-Plane 10 depends on this information as well, and X-Plane 10's global spill and global shadowing algorithms are more sensitive to incorrect categorization of objects than X-Plane 9's forward renderer.

In particular, you should have glass for the airplane windows in an attached object tagged as type 'glass'; do not attach your glass to the cockpit object, which cannot be categorized as glass. If you have an old plane with glass in the cockpit, consider cutting the object in half in a 3-d editor and attaching the glass separately.

(You should also use our prop disc animation, rather than use an OBJ for prop discs; the OBJ format doesn't contain the z-buffer tricks necessary to make the prop look right.)