Blender 3D: Noob to Pro/Enter the World
|Applicable Blender version: 2.70.|
The World settings control the background or sky settings for your scene. A scene doesn’t have to have a World, in which case, the background will simply be black. If you save your images with a transparent Sky setting, the background doesn’t matter. But in other situations, you will want to control what appears here.
Here is what the top two panels in the World Context look like in a new default document. (Settings further down for Ambient Occlusion, Environment Lighting and Indirect Lighting will be discussed later, when we discuss lighting.)
“Ambient Color” is a sourceless, shadowless light, coming from all directions, applied to all objects. Trouble is, its effect is very “flat”, i.e. it washes out detail. It's probably better to use the Environment Lighting or Ambient Occlusion options (in panels further down) to soften murky shadows.
With none of the boxes checked, “Zenith Color” has no effect, only “Horizon Color” does. The sky will simply be a flat expanse of this colour. Selecting “Paper Sky” and “Real Sky” on their own has no effect, they work only in conjunction with “Blend Sky”.
Check “Blend Sky” on its own. Now the sky takes on a gradient from “Zenith Color” at the zenith (straight up) to “Horizon Color”, not at the horizon, but at the nadir (straight down).
Check both “Blend Sky” and “Real Sky”. Now you get “Horizon Color” at the horizon, with a gradient to “Zenith Color” at both zenith and nadir.
The effect of “Blend Sky” with “Paper Sky” is a bit more subtle. It means the horizon is always in the middle of the image, regardless of the orientation of the camera. The effect is more noticeable if you check “Real Sky” as well, otherwise it looks little different from “Blend Sky” on its own.
Here is an example with contrasting horizon and zenith colours. I also set the camera field of view to 90°.
With only “Blend Sky” checked, a render looks like this.
With “Blend Sky” and “Real Sky” checked, this is how the render comes out. Note how the cube is noticeably off-centre relative to the horizon band, because the camera view is at an angle to the horizontal.
With all three of “Blend Sky”, “Real Sky” and “Paper Sky” checked, the result is this. The cube now looks like it is on the horizon, even though the camera angle is the same as the previous image.
You can also add a texture to your sky. That will be discussed later.