Sky Dome problems

Ged

I always encounter the same problems when making a sky dome work well in game. The main issue is just that the player doesnt look up much so they dont see all the lovely clouds and details they just see the blurry tightly mashed up clouds on the horizon. How do games like rage or assasins creed or the new halo do it?

Do they use a separate camera with a different fov for the skydome? or squish the skydome down so that the user sees more?

Neox

from what i saw in several productions its just a scaled down hemisphere

Snader

You should ask yourself the question: 'why are my clouds blurry and mashed up'. Sounds to me like you're using a hemisperical dome with a cylindrical unwrap. And yeah those are stretchy - blurry on the edges, squished in the center. Have you tried using a different kind of unwrap, such as maybe using a subdivided cube as a sphere?


second sphere.

This makes it rather easy to apply 5 textures (4 sides and a top; don't need a bottom for a skydome) and have a nicely even texel density. Plus, as a bonus, it saves a few polygons.

Ged

great tip snader that could be worth a try. How would you get a sky like this http://www.cgskies.com/sky.php?sky=221&type= mapped to the uvs of a subdivided cube style sphere? it would be a massive mission to wrap the texture to the uvs?

Snader

The simplest way would be to make and unwrap the cube-sphere (first unwrap the cube, then subdivide). Then make a regular sphere with that cylindrical map applied to it. Then bake/project from the regular sphere onto the cube-sphere. It's what I did for my Earth cubemap experiment.

As you'll see though, there are lots of stretching artifacts due to the inaccurate nature of cylindrical projections. Which means you'll have to clean up the poles of the sphere quite a bit. Luckily, the most noticable errors will of course be in the center of the top cube-wall, which means you have a nice flat square to photoshop.

Oh by the by, if you simply subdivide a cube in 3DS Max it won't become quite a perfect sphere, so make sure to toss a spherify modifier on that sucker. (Not that it's all that important since a skybox/dome isn't exactly an accurate representation of space anyway, but hey)

Ged

neat, I will have to try that some time, pity Im on a mac at work and dont have maya so baking textures from one mesh to another can be a little tricky just cause I dont have the tools. Anyway I found that one of my current sky domes looks pretty good if I just scale it down to half its size on the y axis and then double the uvs on the x axis . Its not perfect but it works for now, I will try the new methods you describe soon when I work on a new sky dome.