If all else fails, read a guide or google a how to video.

What do you call a proper chimney?

You can have a fire running inside with no chimney at all if you have a high ceiling, because smoke despawns.

Smoke "particles" are almost 2 meters. You need a big enough opening to let them out. Make sure you have at least a "full square" opening for exhaust.

a "proper" sized hole IRL is not the same as in Valheim.... The "smoke" particles are a physical entity in Valheim and are nearly the size of one full floor tile, so the ventilation hole must be that big...

Rather than trying to explain it, just go to YT and look up firespark81's video explaining everything you need to know about how smoke works in Valheim.

put a roof on the chimmey and leave the wall parts open under roof of chimmey for one section above the roof line

What do you mean by proper? Everyone else has figured out how to keep fire going. Let smoke out, don't let rain fall on it, pretty much the only criteria.

or a triangle type roof on top of chimmey

As previously mentioned it does need a roof for when raining. This video provides a good explanation of venting smoke: https://www.youtube.com/watch?v=i5wvMTLYxWI&t=4s

I tend to put a 45 degree corner roof on top of the chimney. It looks pretty dumb, but gets the job done.

You have fire. Fire make smoke. Make so smoke doesn't gather inside house. It's not rocket science.

Originally posted by Ragequit Inc.:

You have fire. Fire make smoke. Make so smoke doesn't gather inside house. It's not rocket science.

That part's relatively clear, but what you have to do to make the chimney protect the fire from rain is weird looking and unintuitive.

Originally posted by ulzgoroth:

Originally posted by Ragequit Inc.:

You have fire. Fire make smoke. Make so smoke doesn't gather inside house. It's not rocket science.

That part's relatively clear, but what you have to do to make the chimney protect the fire from rain is weird looking and unintuitive.

I don't find it is. ANY roof piece protects your campfire from rain. Whether you can make it look good (or even want to) is up to you.

Originally posted by ulzgoroth:

Originally posted by Ragequit Inc.:

You have fire. Fire make smoke. Make so smoke doesn't gather inside house. It's not rocket science.

That part's relatively clear, but what you have to do to make the chimney protect the fire from rain is weird looking and unintuitive.

It truly isn't. Cover the fire. 4 pieces + a roof is all it takes. The fire is covered.

Do you find, in the real world, that most chimneys have roofs on top of them?

(Also, if you pick the wrong roof it can count as sealing the chimney despite plenty of gap area.)

Originally posted by ulzgoroth:

That part's relatively clear, but what you have to do to make the chimney protect the fire from rain is weird looking and unintuitive.

How come? Real chimneys also have to protect fireplaces from rain. The game is pretty forgiving in that any roof directly over a fire seems to guard it from rainfall. I'd probably agree that the amount of space you need to allow for smoke to escape is unintuitive though.