The f_canvas_wall and f_canvas_door, not being actual walls and doors, don’t line up or rotate properly. The doors won’t ‘attach’ to the walls and the walls won’t make corners if a door is next to it instead of a wall.
Additionally in a site called “campsites” there are vertical picket fences (t_fence_v) lined up horizontally.
I made and assigned those tiles in the config for the Chesthole tileset. They won’t attach because f_canvas_door and f_canvas wall are two separate things and, being furniture, will only attach to themselves unlike terrain doors and walls which “connect_to_wall”.
I don’t really think there’s an easy way to fix it without more “connects_to” flags (ones that will work on furniture). And me knowing nothing about coding means I have no idea as to the difficulty of fixing it.
I suspect that the fence issue can be fixed in the tileset config. t_fence_v and t_fence_h should be functionally identical to ordinary fences ever since the PR I linked in the other thread.
Connect groups for furniture (as opposed to terrain) are another matter altogether, and that would need to be added as a new feature request. I ran into the same problem with canvas walls/doors in my iso tileset, and iirc I just did an unsatisfactory workaround by making the tiles cube-block style.