I seem to have stumbled across a way to represent 2 or more height changes within the toolset with only one additional terrain type. If I have a height change of 3M and I have another terrain type of 6M, and I want to combine them, normally I cannot have anything but corners representative of those individual terrain types. I cannot also transition from the 0M or 3M terrain to the 6M terrain without a special tile, even though the transition from 3M to 6M is just another +1 height transition. You simply cannot do two height transitions on a single tile from inside the toolset. With gff editor, you can do this all you want, as long as you know how to poke at the data.
So I was thinking that I needed a way to shift from +1 at 3M to the 6M other terrain. Shift.... what do you do before you shift in older cars? You apply a neutral setting to the gears. So what I needed was a neutral type of terrain.
Within this neutral type of terrain, I can pack duplicates of other tiles which share a height. Then by designating a corner of the tile as Neutral, I can stitch together the +1 height transition and the 2 unit height other terrain.
Because the Neutral terrain is double packed (or more) that gives a base of 2 tiles that could spawn at the intersection, so without further alternative tiles for that intersection, worst case scenario in the toolset is that I have to hit erase once or twice to get the tile to switch to the other.
So with this Neutral corner, I can now portray a tile which is top left to bottom right: grass, mountain, chasm, grass +1, and then place that adjacent to a tile which is grass+1, mountain +1, grass, grass +1. Below is an illustration.
In the toolset, the 0 and the adjacent +1 listed in green represent the proper acceptable height transition mechanism in the toolset. The M and +1 listed in red are not a matching height transition, because you cannot match a height transition of one terrain to a different type of terrain. So basically, you cannot do this in the toolset.
The second image shows the same tiles but with the trouble corners set to a third terrain type, Neutral. This allows the tiles to properly match up with applying a height transition to the other corner.
Neutral +1 can either be specifically defined, it could clone the set from Neutral 0, or it could be omitted, disallowing either corner from using any height transition.
I picked this up after trying to make some of the tile combinations in Torchlight 2, where they transition 2 and 3 tile heights together easily. While their map maker is very different from NWN, the basic concept of the tiled area is the same, so I figured there must be some way to pull it off in NWN.
Now I can easily transition two heights at once, but in the current iteration of my tileset, the mountains are actually more than 2 transitions high. I had originally gone with 900 for mountains and 150 for grass raise, which left me with 6 transitions to reach the higher level. I might as well do that with an area transition to a higher place, or via doors, like a cave or something, but I wanted to be able to actually trek up the mountain.
So then I changed the mountain height to 600, while setting the normal height transition to 200. I could reach the top of a mountain section in only three transitions, but still I couldn't do that in the tileset.
In TL2, they have alternate mountain edges, which show 2 or 3 transitions as tight unwalkable steps on the height transition. The character to tile size ratio of NWN is slightly different, so I would like a walkable ledge, much like they have in Dungeon Siege 1. I figure I can now do that with these Neutral corners, and a crosser called ledges or steppes. I can either portray one lower ledge, one higher ledge, or both ledges using the same crosser used against the neutral corner. This opens up a large array of cave, bridge, and mountain pass options for the tileset. It also completes the needs I had for the underdark tilesets!
