Need ideas for a 3D illusion...

I'm trying to make a cave in my map, and because of the height variation around the cave, it's possible to look down on it. I want the cave to not stretch to the ceiling, so normally one would use a sky paradox in this case. However, because you can view it from above (in front of it), using a sky paradox would make the cave look flat, like it was a paper cutout standing up. I'd like to be able to "see" the roof of the cave, even if it means you can't stand on it.

So I decided I would try to go for some sort of vanilla-based approach with flat bleeding and middle textures, and making the caves lower walls instead of solid. Didn't go so well... The mouth of the cave introduces all sorts of little problems, with flats bleeding over the middle textures and not covering up the roof properly. I fear what I'm trying to do isn't quite possible.

I'm using floating middle textures (like a bridge) at the moment, but it's not nearly as convincing as I would like it to be. Some custom textures would make it look better, but it's not satisfying enough. Here is a shot of what it looks like with the "bridge" method:

http://img63.imageshack.us/img63/7016/sample.png

I sorta made a pattern of triangles, so you wouldn't see any gaps if above or inside (they're required for my slopework anyways). Does anyone have any ideas how I produce a similar form of architecture as depicted in the screenshot, using some other method? The mouth of the cave needs to be about 384 deep before it disappears into the sky wall behind the cave.

The wad is intended to be ZDaemon compatible, so I'm limited to vanilla, Boom, and ZDoom 1.23 tricks. Any help or ideas are appreciated! Thanks. :(

I've wondered why there wasn't a flat for the texture you're using for the walls. Just resize it if necessary and use that as a flat on the sectors flanking the cave and it'll blend in.

That's what I was talking about with the custom textures for use with the bridge method. Sure I could do that, but because the light levels need to be adjusted, so it darkens as you go into the cave, you would see the textures from the roof being shaded as well. I don't think using floating textures alone is going to be a suitable solution. :/

Hmm, true. If you use the boom transfer lights, or if there's even sidedef specific ones in zdoom you could individually make the sidedefs a brightness and the floor and walls another (make sectors around each in boom then transfer floor brightness). Then add more sidedefs that will be lower down, say 32-64 pixels, that will be the ceiling of the cave, and have those be the same brightness as the cave.

What about Boom fake ceiling and floor?

Jodwin said:

What about Boom fake ceiling and floor?

I never heard of that before now -.- Yea use that instead.

Jodwin said:

What about Boom fake ceiling and floor?

You would be able to see the both the upper and lower sectors from the mouth of the cave, resulting in HOM.

The only think I could think of is kinda lamely simply having lots of mid textures that kinda fade off. Straight textures would be obviously 2 dimensional slats, but maybe more cave like wavy/bumpy textures might make a better 3d cavetop illusion (kinda like this pic, but couldn't find a better pic:
http://koti.mbnet.fi/pkl/tg/examples/Hills-20.jpg
)
Actually, I guess the bottom/inside of the cave would have to be wavy too or you'd see straight slats from below. Still they'd appear 2 dimensional if viewed from the side (and would need backsides textured with mirrored copies probably) Or maybe not smoothly wavy; more angly to match the angly triangle floor or whatever.
I couldn't think of a way to make boom fake ceiling/floor work.

This is about what I meant, it needs more midtextures blocking the light on the sides within the cave but it works kinda. Just resized the rock* texture to make the flat and a smaller texture that goes with it for the midtextures, used transfer brightness on most of the floor, and a lot of time (probably wasted :P).

Perhaps use something simpler, like try to cover open spaces with an edited hanging sprite? make some icicles or stalagtites or something....

Or make smaller trianges and make the sides one solid color, then use the secondary sky texture as a solid color, and apply that to that sector.

Can you make overhangs in your canyon-ish area that block the view of the roof of the cave?

Thanks for all the replies guys.

The map I'm working on has a very pristine, surreal nature, and I've taken a lot of care to make everything look "perfect". I've found a solution, which may or may not make the cave still viable, but at least I can maintain the quality of the map without resorting to middle textures. Instead of rushing things, I think I've come up with something with far more potential to look nice.

The map is a gigantic map that takes place on a mountain side. The idea was to have a cave at the bottom which players could enter and wrap around to the top of the mountain. Something sorta like the warp tunnel on Pac-man (note the map has nothing to do with Pac-man though :)

Instead of using a cave right on the wall, I've decided to make a "land bridge" to connect both the upper and lower sections of the mountain. On top of that, I will use fog to conceal a cave until the players are relatively close to it. That solves all my problems. I can use a sky paradox around the cave to make it seem shorter. When the player gets close enough to see the cave, they are low enough and cannot get higher to ruin the illusion.

So yeah, that's the idea. But it will only work if the fog doesn't obscure sky, which I'm going to test briefly (I can't recall otherwise). Hopefully this works like I intend it to, otherwise I'm back at the drawing board. 9_9

Edit: Looks like it's going to work out. I just need to get the fog to fade to the right colors so it blends into the gray/white sky, and I should be set. Thanks to all those who offered their advice. I would have probably settled for something less effective if it weren't for all the idea bouncing here. :)