Graphics Reference
In-Depth Information
ing a completely separate image gives better results and faster renders. To set up the environment by using
both images, you will need to follow these steps:
1.
Load the desired environment (either a preset or an outside image).
2.
Duplicate the environment item (choose Item
⇒
Duplicate, or right-click the environment and choose
Duplicate).
3.
Select the first environment and in the Properties tab, deselect Visible To Indirect Rays.
4.
In the second environment, deselect all options but Visible To Indirect Rays.
5.
Select the image in the second environment and replace it with the blurred, lower-resolution version.
With the illumination portion of the environment simplified, the render settings can be lowered without a
reduction in quality. The Irradiance Rays value can be lowered to 256, and Irradiance Rate can be increased
to 5.0. Both of these changes result in a smoother and faster render.
Figure 11-37
shows the result of the
altered environment. This image was rendered in just over half the time of the previous image. With this
kind of increase in speed, other settings (for example, Antialiasing) can be increased while render times re-
main reasonable.
Figure 11-37:
Blurring the illumination section of the environment can reduce render time significantly
without loss in quality.
Physically Based Sun and Sky
The accuracy of time-relative coloration makes physically based daylight simulation a compelling option
for exterior architectural renders. This option must be enabled in both the Directional Light that will act as
the sun (providing direct illumination) and the Environment material that will simulate the sky (indirect il-
lumination). Because time of day, global position, and date can all be adjusted, and the coloration of both
sky and sun update dynamically, this is also an easy solution. The downside of this kind of lighting is that it
offers almost no effect on reflection and no real background image (just a color gradient). This means that
camera angles that show the environment in any way are not well suited for this kind of lighting alone.
