Tiletypes is confusing me. A lot. Maybe not just me, seeing some messages in this thread.
What I noticed so far:
It does not seem to report invalid commands. Even every invalid command just reports the current settings.
There is a "help" feature, but not for the main commands "help filter" or "filter", just for the options. That help is available for the options would probably be better indicated in the title, like "Filter/paint options (see help [option] for details about individual options):" - not at the bottom.
The main command synopsis also is wrong. "filter / f [options]" really is like "filter / f [option] [option argument]", passing multiple options does not work.
I also do not seem able to paint into open space, or manage to place a material from a mod (mithril wall from masterwork df, for instance)? Maybe I missed something, or perhaps this is a tool to "change tiles" rather than "paint map tiles freely"?
The problem is that the way this works in DF is pretty confusing and the tool doesn't even try to hide that.
here's some examples:
paint sh wall
paint m soil
This will turn tiles into soil walls.
filter sh floor
paint sh ramp
This will turn floors into ramps of the same material (not fixing ramp tops. You have to add those too on the z-level above)
You can nullify any setting by using the value ANY:
filter sh ANY
Now, let's do something interesting:
filter sh SAPLING_OK
paint sh TREE_OK
Turning saplings into trees!
Tiles in the game are really represented by a number. The attributes used in tiletypes just try to make sense of what the number represents and turn it into something a bit more logical. Shape determines the general shape of the tile. Material the general material (not specific!). Variants add different look to tiles that would be otherwise uniform - there's 4 variants for every type of grass material, 4 variants for stone floors, etc. The special attribute is things that didn't fit the scheme.
Now, this has some limits and non-obvious problems. You can't use a specific material. Stone is fine. Soil is fine. Grass is fine for a subset of shapes. The final material is determined by local geology, the mineral veins present and map features (like hell and adamantine tubes). All materials it can use can be listed by using 'help mat'. All shapes by 'help sh'.
Your mod material isn't part of the tile type - you'd either have to have it as a layer stone or part of an already existing vein for it to be placeable by tiletypes... and then you'd only be able to replace already mined tiles, for example like this:
filter mat VEIN
filter sh FLOOR
paint sh WALL
Replace mined out veins with walls.
You definitely can paint tiles over empty space. It just has to exist first. The game divides its map into blocks of 16x16 tiles. If the block would be entirely empty (every tile is empty space), it doesn't even get created. You can see this with the 'k' cursor while looking above the terrain. If you get no description for a tile that should be empty space, its block isn't created. Tiletypes can't create such blocks. You'll have to build constructions up there first - build stairs into the sky for example.
Every other problem you have with it can be considered a bug.