Lighting: The Easiest Thing That’s Tough - Blender Foundations: The Essential Guide to Learning Blender 2.6 - page 111

mend that you use them. Set your start and end clips manually by adjusting the appropriate controls. The
goal when doing this is to get the clip area as small as possible while still encompassing everything in your
scene that needs to cast and receive shadows.
Filter Type
I prefer to use the Gaussian filter type, which produces rounded smooth shadows. Both the tent and box
filters tend to produce more angular results, with obvious beveling in the shadows at the corners.
Deep Shadow Maps
I had mentioned that the other type of shadow map you might use is the deep shadow. Regular shadow
maps have problems with transparent objects. All they know is that they've encountered a surface, so they
mark it and move on. In real life, light shines through transparent objects, which can cast partial or even
colored shadows. This is one of the problems that deep shadow maps strive to alleviate. If you need shadows
to be cast by transparent objects, try switching to deep. Deep shadow maps also give significantly better
results for elements like hair and fur, which we'll learn about in Chapter 6.
This map generation style uses significantly more memory and processing time than a standard map, but
if you need those features, well, you need those features. When using a deep shadow map, reduce your
size requirements. A standard map that looked acceptable at a buffer size of 2048 pixels will look nice as
a deep map at only 512. Keeping standard sizing for deep maps will eat your RAM so quickly there'll be
a sonic boom.
Those are the mechanics and controls for the directional lighting tools. We'll use them to light our room
scene after we learn about the nondirectional tools.
Nondirectional Lighting
Nondirectional lighting does not come from lamps. It is calculated as an overall solution for a scene. Some
renderers include global illumination, which takes the actual effects of light transport into account. Blender
is not one of these. To achieve a similar though inferior effect, Blender uses a technique called Ambient
Occlusion (AO). A scene “lit” with AO
looks as though it were outside on a
thoroughly cloudy day. Figure 5.16
shows our scene lit with nothing but the
Environment Lighting portion of AO.
As you can see, it's not bad. It provides
overall illumination, while darkening
creases and the places where objects
contact one another. Although it isn't
sufficient for any kind of believable
work, it makes a great basis for an overall
lighting solution. Environment Lighting
settings are found in the World context Figure 5.16 Environment Lighting with Ambient Occlusion.