Skybox vs SkyDome

You may have come across some games using either of these to simulate a sky or some even use both (as in Unreal). So which one to use and when?

Back in the early days of 3D computer games, polygons were expensive and every face took up precious processing power. Hence, a skybox was the best way to go then. However, there are problems with skyboxes.

1. They look "boxy" if textures are not done properly
2. The perspective looks screwed up (hey, it's a box okay!)
3. Totally unsuitable for games with flying vehicles/creatures as the higher you fly, the more obvious the sky looks fake.

Nowadays, computing power is way better and a skydome hardly makes a dent on processing power. It has significantly more faces but the advantages are:

1. Everything the skybox screwed up on

So, that means sky boxes are useless now right? Not true. Skyboxes still are useful. Remember, every resource we squeeze performance out of, frees more resources to add to other things... better AI, bigger textures, more animation, etc.

So in conclusion, you will probably use a skybox if say, you are in a limited viewing area (eg. in an enclosed building but can see the sky through windows) or you are outdoors but are blocked by fences.