For "dungeon" type settings, where there is no skybox, I was trying to figure out a good ratio to trick the viewer into thinking short distance was much longer. Having seen at least one way of doing it in SCL, I was also thinking to do a vertical bowing, based on some artwork I was using for crags, which come from a set of Lovecraftian concept art for something (not sure what). If I can assume that the maximum height in an area is 140 meters, and the maximum depth is 30 m (maybe it is 25 based on my exploration in the badlands tileset), perhaps I can create a set of room-like tiles which bend inward as they go up. Using two types of "surround" tile, I can display a panoramic deeper area, as well as a very hard enclosing surface around, and even into, other walkable tiles.
While trying to flesh this out this morning, I came up with these terrains:
Chasm - a base terrain with nothing but stalagmites and strewn boulders in a pit. Instead of EVER reaching the bottom, you'd traverse a series of bridges from tower to tower, with occasional islands ringing a larger -tite-mite column. The column an also serve as stairs to a higher level which connects at this point.
Chasm Bridge Crosser - as mentioned above, this bridge passes from column to column, or touches a few taller stalagmite mounds from below. Tower parts within the bridge system can offer ceiling regions visible within the visible depth of the environment.
Cave/Solid rock - a base terrain of enclosed unwalkable region, into which you place corridors or prefab cave rooms. One or two of the cave rooms should open into other terrain types.
Cave Corridor (type A: thin tunnel) - This thin tunnel represents mine shaft quality tunnels between dungeon style rooms
Cave Corridor (type B: wide tunnel) - This wide short tunnel represents an expanse of natural cavern and has a nice flat bottom made of hard-packed debris. Additional placeables could be built to turn any given wide tunnel into a partially collapsed cave run with fallen cave-clouds or other formations which have come loose form the ceiling.
Cave Corridor (type C: lower chasm) - This thin tunnel, with no visible ceiling, represents the bottom of a chasm, or deep drainage cleft in the surrounding rock. The walls could come in some really interesting shapes which block 1st person, or top-down view at many points. This corridor could also be used as a height transition change if T-tile are created with a ledge system.
Cave Rooms - A great number of cavern rooms, both natural, or man-made grottoes, should be created in the size range from 1x1 for closet spaces, 2x2 for common combat locations or treasure filled places, 2x1 for unique transitional halls, 2x4 for unique transitional rooms, 3x3 for smaller boss rooms and great features, such as camps, or 5x5 for greater boss rooms and fantastic locations. Additional 3x3 rooms can bridge the transition to other areas, such as up and out, down a spiraling tube, great stairwells, or portal locations.
Surround Wall - an unwalkable terrain which leans into adjacent tiles using a hyperbolic curve, fully blocking view and access to adjacent areas, or off-map regions. surround wall can also lend a ceiling mass which can be seen, even in the darkness of a cavern.
Surround Chasm - a very deep region that trails off into darkness. The expanse is so wide that you cannot make out any features of another side. Down below, there may be mushrooms or other things visible. Everything at a distance should be down-scaled to exaggerate distance. This terrain should only be placed near chasm terrain, so that the player can never look directly at the scale offset in an adjacent tile.
Dome Cavern - a base tile which can go inside the solid cave tile, or out inside the chasm base terrain. This region easily lends itself to simple height transitions, or 2 at once, without getting in the way of any other transition types. This is also the best place to create building structures, or open markets.
Dark Lake - A water terrain type which you cannot (and would not want to) enter. This would be available to a flat walkable terrain, such as the dome cavern, only.
There is no need for water within the dungeon areas, and no need for stream type crossers, as the room-based areas can have them built in already.
Since everything will be corridor-connected, doors, secret doors, and open hallways will need to have standardized door placements.
Given the quantity of tiles available in all SCL tilesets, there is enough variety to give a great base to this kind of underdark dungeon system. All the art I have downloaded over the last two years related to caves, as well as 3d maps and panoramic views of actual cave rooms (from national park service stuff), will give an almost unlimited supply of new tile groups which can be released in packages later, after the base is available.
