Game Development Reference
of distance from the front to the back is about 4000. Change the
Focal Plane Thickness value to 4000.
The blur disappears, but that's okay. We now need to specify
where we want the blur in terms of 3D depth. We adjust that with
the Focal Plane property. If we take this to 4000, it will blur the
background. But we start to see a little problem here. As we blur
the background, the rest of the image starts to blur a little as well
(Fig. 2.15 ).
Figure 2.15 The result of
adjusting the Focal Plane
Thickness and Focal Plane
What we need to do now is to adjust the Focal Bias param-
eter. When using depth of fi eld on a real camera, the width of
the aperture determines how shallow or deep the depth of fi eld
is. Let's say that we only wanted the wrench of the table in focus,
and everything else closer or farther away out of focus. That is a
small object, so we would need a more open aperture to produce
a more shallow depth of fi eld. We can simulate a narrower depth
of fi eld by adjusting the Focal Bias property.
I'm going to take the Focal Bias value to 0. Adjusting Focal Bias
throws off your blur a little, so now I need to fi x my Focal Plane
value. I'll take the Focal Plane value to 3600. We now have the
entire background blurred, but the blur stops right at the garage
door. The plant right outside the garage door is blurry, while the
garage door itself is sharp because of our narrow depth of fi eld
(Fig. 2.16 ).
What if we wanted to make our viewers focus their attention on
what was happening outside? That might be challenging because
there's a table in our way and a really sexy yellow car, too. Simply
change the Focal Plane value to −4800 to make the foreground
blurry and the background sharp. It may sound weird, but viewers