How is it going to opened and closed? The player does not normally interact with objects directly, only dwarves. If there's no lever-link then it will be like a lever itself then? and a dwarf will cue a job to open or close it? sounds like a bigger change to the code.
Not really, we already have levers do something like that. And many people would like the same done with doors. Nor did I say that windows should do this, but it is an option.
why not make it sealable? It would give it a little usefulness to justify the coding time. And shutters in the real world do tend to keep the elements out, the suggestion is just taking it to dwarf fortress extremes.
I would be fine if either way was done. Shutters pre-1400's were just meant to keep most of the rain out, most of the time they were ineffective. It would be like having nothing on your window but blinds. And how can you compare a rain storm to a tunnel full of magma?
Doors don't tend to stop Water or Lava in the real world either, should we make that change right now?
Back in 40d only floodgates stopped liquids, this was changed overnight so that doors stopped liquids too. Doors essentially leave floodgates obsolete, with no delay doors close instantly while floodgates take almost forever, this instantaneous shutting cuts out a lot of potential Fun. I, and many other players, consider this an exploit. So why not switch back?
Effectively the suggestion will be a glassless window which can be opened and closed, with a stone or metal (or wood, glass,clay etc) shutter. Why not just say this is the equivalent of a hatch or a door?
When did a window become the equivalent as a door?
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Perhaps a window would not allow movement through it regardless of whether it was opened or closed, opening or closing merely prevented people from seeing through it. This still has advantages, it would prevent goblins from shooting through, additionally it would prevent dwarves from freaking out because your dining room had a few windows to the outside world. But didn't allow for exploits, you could still hook it up to a lever or you could forbid them all like a door.