Having fun documenting this as I go. I'll have to update the basic tileset tutorial when this is done.
So far, I've completed a comprehensive diagram showing how to make what I call shared crossers, inclusive crossers, and exclusive crossers, as well as all the data to mix 2, 3, or 4 terrain types together, and the three types of crossers allowed on those tile combos.
So here is what those are:
A Shared Crosser is any type of crosser which can go between any two terrains, including the same adjacent terrain. For example, you can place my new forest crossers in stead of forest terrain, and that forest can be placed on rocky ground, or on plain ground, but can also come out of rock faces caused by a height change, even if that is stunted. In all situations, there are 15 tiles required to make a full set of crossers for any given corner combination. For example, if you have a tile corner combination of ABBB, you have 15 tiles with crossers on them with this corner combination to fulfill the crosser's needs. Because any basic tileset with a height transition has not just ABBB, but also AABB, AAAB, and ABBA (and sometimes BAAB), as well as AAAA, you need a lot of tiles to finish a complete set of shared crossers. Expect to make about 75 tiles, if not 90, just to combine two corner types. I would suggest rarely using this tile type, unless you intend to automate the process of tile making.
Less strenuous is the Exclusive Crosser. If shared means that any two corner terrains can share this crosser, exclusive means that only equal adjacent corners can contain this crosser type. There are only 9 tiles to create a full set of Exclusive Crosser tiles for two-corner-type areas. This is because in a tile such as ABBB, only the B part of the tile can contain 1 or 2 crossers. Likewise in the AAAB, only the A portion can contain 1 or 2 crossers. There are no instances of ABBA or BAAB tiles for this type, unless you make special diagonal crossers. This counting does not take into consideration the full AAAA or BBBB tiles. This small crosser is sufficient for making roads, non-cutting rivers which might include waterfalls, and ledges on mountain faces, and is commonly used for standard walls.
A common type of crosser we are all familiar with is the Smooth crosser. I categorize this as an Inclusive Crosser. You include only the areas of the tile where two different corner types meet. In the smooth crosser, you only smooth height changes. Other types of crosser which would use this method are stacked stone retaining walls, hill-cutting streams (without waterfalls), or elevated walls ringing a height elevation. This crosser requires 18 tiles to complete a full set mixing only two corner terrain types. In the case of streams, removing 4-edge combos will reduce your tile count by 1. Removing 3-edge combos will reduce your tile count by 2.
In all situations, to cross three or 4 types of terrain corners, the shared crosser will always require the full 15 tiles per combo, unless you skimp.
To cross 3 terrains with an exclusive crosser, only 6 tiles are required. You cannot use an exclusive crosser on 4 different corners of terrain.
To cross 3 terrains with an inclusive crosser, there are 27 tiles required to fill the set. Add 9 more if you make special accommodations for diagonal tiles like I do to account for their dual nature. To cross 4 terrain types, there are only 20 tiles, and no reason to worry about diagonal tiles, unless you want diagonal height ramps, in which case, add at least 9 more tiles, of which one joins 4 terrain types in a single jump.
I'm now teaching GMAX how to make this combination output in 3D, and then I'll share the files, probably as an exported simple tileset without the burden of texture. Should be pretty easy, I had already done this before years ago with my 4+ height change tileset.
