Graphics Reference
In-Depth Information
Using environment lighting on a roofless model provides even lighting and makes it easier to get a sense of
the interior space. At times, however, a more realistic lighting solution is needed. Much of the decision de-
pends on the needs of the project or personal taste. Creating a mix between environment lighting and stand-
ard CG lights (Point Lights, Spot Lights, and Directional Lights) is key to successfully lighting a scene in
this manner. Setting up daytime and evening renders shows good contrast between possible lighting setups
and allows you to make variations that incorporate some elements of both scenes.
The first step before creating the lighting for a closed structure is to actually create a closed structure.
Adding a roof to the building can be done very easily because of the way the structure was built. At the top
of the structure, a solid loop of edges runs around the entire exterior of the building. Double-click any edge
that runs around the exterior wall at the top of the model. With the entire edge loop selected, press the P key
to create a polygon in that space. The new polygon acts as the ceiling. If it is visible from the top side of the
model, it is actually facing the wrong direction. In such a case, select the polygon and press the F key to flip
it so that it is facing down toward the interior of the building. Finally, apply a new material to the polygon.
Make it white with a high Diffuse Amount (about 90%). Because a lot of light in the scene will actually
be bounced off the ceiling, it is important to make the ceiling light colored. After making the ceiling, the
lighting process can begin.
Creating a Daytime Scene
Lighting in the daytime scene can be created, for the most part, by implementing physical sun and sky prop-
erties. To set up the sun and sky, follow these steps:
1.
Select the Directional Light in the scene and enable the Physical Sun option.
2.
Set the Time to sometime in the late afternoon or early evening so that sunlight comes directly into
the windows.
3.
Rotate the sun angle by using the North Offset option. A setting of about -12ยบ should make the set-
ting sun shine straight into the sunroom.
4.
In the Shader Tree, open the Environment item and select the Environment Material (if there is an
image above this layer, either disable or delete it).
5.
In the Texture Layers (in the Properties tab), change the Environment type to Physically-based Day-
light. This setting dynamically adjusts the environment coloration and brightness based on the time of
day selected in the Directional Light.
6.
For both the sun (Directional Light) and the sky (Environment), disable the Clamp option. This
makes the exterior of the building very bright, but causes the light coming in the windows to more fully
illuminate the interior of the house.
7.
Because natural daytime lighting is largely caused by bounced light (secondary light), more bounces
need to be turned on in the Global Illumination settings (first choose the Render item in the Shader
Tree list). Under Indirect Illumination, set Indirect Bounces to 3.
This initial setup is equivalent to opening all the curtains and blinds in a building and turning off all the
lights. Some areas (such as the kitchen and entry hall) will have very little light bounced into them. Other
areas (such as bathrooms and closets) will be totally dark because there is no access for outside light into
these spaces. To brighten these spaces, simply place a few Point Lights around the scene. Place the lights
near the ceiling. After putting a few lights in the scene, you may notice bright specular reflections on some
of the materials. In the case of materials that have bright specularity, select the material and turn off the
Specular Amount. Also, make sure to turn on some Reflection Amount if it had been linked to the specular
via the Match Specular option.
Figure 9-39
shows the daytime lighting.
