in the toolset there is the chance to rotate the " free" middle terrain tiles like w w w w and other specular tiles like straight crossers, cross crossers etc, there is also the chance to "rotate" among the available tile variations for the given tile (or am i wrong lol). cant remember how, but shound be a combination of mouse right click with ctrl or shift or alt....
about the texture rotation, from my perspective i say tverts are not connected with texture rotation. aka when you rotate the tile say by 90 degrees, the texture with a trimesh "rotate texture" option applied, the texture doesnt rotate, its always aligned with an absolute direction given by the engine. but the tile and all its components so including the mesh and its tverts, do rotate. to check this in terria, and i may very well be wrong and you right and it doesnt work, no animloop should be turned on. just flat water, with the mesh opacity turned to 100% to skip transparencies. all water tiles should be seamless. if you rotate water tiles, the texture should stay the same (this can be better viewed in river crosser straight tiles, rotating the tile by 180 degrees). also, if you appy an animloop to a single water tile and then rotate it the flow direction should change while the texture orientation shouldnt.
i am almost sure i didnt get isssues with trimesh rotate texture, and the seams i got were only with animloop turned on, even if i cared a lot to synch all the animesh animation frames and such, it seems the engine clock doesnt synch animations, so each starts with its own timing '>
correct me if im wrong, i just cant check it without nwn eheh
about the multiple layered water, I agree its a good way to go, it does disguise the seams a lot (i did some three or four layered water in the tiles where the stream crossers blends with the water terrain AND OR in the T shaped stream tiles, dont remember, to disguise the unavoidable seams of two merging water flows) and it can even give more "life" to the water itself, looking forward to see your results '>
about the terria/ud mix, i didnt really ever thing about that because i made the ud tileset a few years before terria, so even if its very unique as tileset, it has a lot of flaws while with terria even if its incomplete i am very proud, i did improve my skills and created something new and different from the other wonderful tilesets i used to study for inspiration
i remember when i was cooking terria I was tempted to start a new underdark tileset, but talking with sixthrice i realized i would never get what I wanted because of the ceilings. basically to get beautiful uneven ceilings that change height in the same cave, you need to use a new terrain for each ceiling height, and imagine the amount of tiles needed when you merge ceiling and floor height variations.... literally dozens of thousands!! so the way to build them should be the placeable way, not an easy project to make, nor easy for the builder to work with...
if you manage to solve the ceiling issue i may be very tempted to reinstall max and nwn and give it a try even if im short on time! waiting to see how you will deal with height variations for interiors without an abnormal increas of tile count '>