I have made an AVI of the problem and title of this thread. The AVI is just over 5 Meg so it might take a few minutes to download. You can get the AVI zip file at the following link.
http://home.earthlink.net/~ronholmes/ the name of the file is "Polygon.zip".
I have showed two things (Prefab and canyon problem) in the AVI:
1. First you will see a short section of my canyon wall and in the for ground a prefab from the prefab directory.
2. In First Person mode I come down from the top of the prefab and hit the horizontal surface. You will notice that the surface appears to be solid both physicaly and visualy.
3. Next I back up and approach the horizontal slab from below. Now you will notice the slab becomes transparent but that there is correct collison detection. I really think in this case that the surface of the slab extends just beyond where the bounding box stops. so in effect you penetrate the surface texture before being stopped by the bounding box. I may be wrong in this case but I am not worried about the collision detection as it is there. I am only concerned in the tranpareiancy problem.
4. I then approach my canyon wall and stop actually quite a ways from the surface as you can see when I pan towards the bottom on the wall. You will also notice that the polygons are starting to go transparent. I then pan up towards the top and you can again see the polygons become transparent dependant on the angle of viewing.
This is the problem that I have been working on for more than two months without a solution in sight. sorry for the poor graphics but that is how it came out after the capture. Now can anyone shed some light on this without really guessing as to what might be wrong. I have experimented so much I think that I might wake up tomorrow morning and find myself turned into a transparent polygon. Thanks for any help.
Ron