I created some scripts to convert square tiles to isometric tiles.
UPDATE! I created a toolbar instead of scripts but it works the same, one different is that you can choose if you want to downscale or not when creating tiles.
An example, I created the tile set in tilesetter and then used my own script to convert it to isometric tiles.
Are there any plans to make this work for a whole tileset at once, where you tell it where the block of tiles starts (or select it) and what the tile size is, instead of manually selecting each tile every time? Maybe there could even be a mode where it arranges sequences of 3 tiles each into iso blocks.
Some people struggle to conceptualize the shapes of things in iso and this would help a lot, but having to convert the tiles one by one keeps ortho → iso from being a viable workflow, though it still looks like it’d be useful for helping with just a few particularly troublesome tiles.
Im planning to also create that kind of script that takes one file and convert all tiles exactly as you described it.
The toolbar is more as an tool that you create ortho tiles and then convert them like walls, doors, vaults, paths etc. Quite handy when you have complex structures and iso just adds extra complexity.