underground spaces: could this work?

I've seen many people ask for the ability to build underground tunnels and rooms. Underground building is impossible with our current terrain engine, because our terrain is just a simple 2d height map. The current engine maps height values from 0 (flat terrain) to 255 (255 meter high mountains.) Values below 0 (underground) can not exist.

Here's my idea of how underground space might be added with a slight mod to the way sims handle terrain.

Perhaps we could add underground space by adding ANOTHER height mapped terrain, starting 255 meters down below the existing aboveground layer. Think: underground mountain range. It would be like stacking two sim's worth of terrain on top of one another, in effect. With the second sims "flat ground" being 255 meters down. The underside of the top layer would be the "ceiling" of the lower terrain.

The same terrain engine could be used for both aboveground and belowground layers. Values of 0 on the underground height map would mean that the underground terrain is hollow for 255 meters down at that point. values of 255 would mean that the underground is solid all the way to the "ceiling", at that point. Differing values in between would allow "tunnels" to be created.

True, you couldnt build tunnels on top of tunnels with a 2d height map and the "ceiling" of all tunnels would be the same height, but you could do sloping floors and you could design a neat warren of tunnels and rooms. Think of it as a dungeon map drawn on 2d graph paper, where the ceiling of all tunnels is assumed to be the same height and you cant have tunnels directly above or below other tunnels.

On the other hand, I suppose you could just leave some of the space empty and build "rooms" with prim. Kind of like an underground skyscraper.

Problems:
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sim coordinates would have to be modified to support a "z" depth below the current 0 depth.

the aboveground map would have to use a value of "0" to mean a "hole" in terrain, an entrance point to the underground space. If you had a hole (0) in your aboveground terrain and hadnt designed any terrain below ground, you would fall 255 meters down when you stepped in the hole. lol. the belowground terrain would probably be designed with values of all 255 as default to represent ground that hadnt been "dug out" yet. trapdoor, anyone? hehe

accidentally teleporting into solid ground would be a bitch. lol. your head asplode.

we would probably need double prim allotments in sims. heh.

camera control would be interesting.

SL's lighting model isnt designed to handle the situation. bright sunny dungeons arent fun.

it might take more sim cpu and memory to have, in effect, two sims in one.

waterlevels. blub blub...

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Could it be done? I dunno. What do ya think? Am I just smokin the crack? This plan would use less resources than a fully 3d mapped underground terrain and might could be implemented using the existing terrain engine.

In my other post, I suggested adding a second, "underground," height map for making underground spaces possible. Here's a different idea: terrain prims. This idea would allow 3d terrain tunneling.

Since we can already use hollow prims, how about adding a hollow "terrain prim." This prim would be like any other prim, except that terrain prims could be placed inside terrain and the terrain would "flow" around the terrain prim, leaving a hole through the terrain. All this would really require is that terrain collision detection and rendering be disabled inside the volume of the prim. Prim collision detection would stay as normal. This would make a hole through terrain and allow us to move through the "dead space" inside terrain. These prims could not, of course, be made phantom. Your head asplode.

It would be like driving a hollow pipe through a mountainside and then moving through the pipe.

With this idea, you couldnt go below "0" on the terrain map, but you could tunnel through raised terrain. And the flexibility of prims would allow building a wide variety of tunnels and rooms.

What do yall think?

Have a look at this thread, a combination of llTeleportAgent() and the private underground space I suggested would let "underground caves" be implemented by residents.

thats good stuff

I think that a flag on each 4x4 land setting that simply turns off the “Bob to surface” feature in the physics engine would be enough.

You can already place prims underground and you used to be able to fly underground while sitting on an object.

Note: You can still be placed underground using the sit offset.

Therefore, if they add a setting to let you turn off the land, you could build underground.

Note: The existing sit teleporters can put you underground.

Edit: There seems to be a Z-order issue when underground.
The ground is all that is visible.
They could be forcing you “View” to ground height.

Never going to happen unless the current terrain setup is changed. I can tell you it's not going to happen soon.

I love the feature idea, been asking for it since 2003

I have confirmed that the "view" now also limited to ground height, however I have noticed a moment of watter/horizon while it moves between sims.

As for difficulty I don't view this is that difficult since the view did work in an earlier version. I just don't think LL see's this as a high priority compared to keeping ahead of the greifer war.

Alternatively, My concept of "Zones" could also be used to carve out underground areas. /13/91/92793/1.html

If LL wants to woo the MMORPG crowd, they're gonna need dungeons.

Like the song says: "If ya wanna play in Texas, ya gotta have a fiddle in the band."

Well, it takes so friggen long for a new place to compose when you teleport to it, maybe we would be better off taking the subway. Then the place where you are going will at least be there when you get there.