Graphics Reference
In-Depth Information
Thus, because the textured world is connected to a socket equal to the value of
0.000
,
we don't see it directly as a background, but only see its effect on the objects lit from the
reflected light or from the HDR image. The World of the blue sky, which is connected to the
input socket of value
1.000
instead, is seen as a background because the light rays shot
from the camera directly hit the sky.
There's more...
Just after the Surface subpanel, in the World window, there is the Ambient Occlusion subpanel.
Ambient occlusion is a lighting method used to emphasize the shapes or the details of a
surface, based on how much a point on that surface is occluded by the nearby surfaces.
Ambient occlusion can replace the Global Illumination effect in some cases, though not the
same. For example, to render interiors with fast and noise-free results, ambient occlusion is a
cheap way to get an effect that looks a bit like indirect lighting.
There is a checkbox to enable Ambient Occlusion, along with the following sliders:
F
Factor: This is used for the strength of the ambient occlusion. A value of
1.00
is
equivalent to a white World.
F
Distance: This is the distance from a shading point to the trace rays. A shorter
distance emphasizes nearby features, while a longer distance takes into account
objects that are further away.
The Ambient Occlusion feature is only applied to the Diffuse BSDF component of a material.
The Glossy or Transmission BSDF components are not affected. Instead, the transparency of
a surface is taken into account. For example, a half-transparent surface will only half-occlude
other surfaces.
Creating a mesh-light material
In this recipe, we will see how to create a mesh-light material to be assigned to any mesh
object and used as a source to light the scene.
Getting ready
Until now, we have used the default Lamp (a Point light) already present in the scene to light
the scene. By enabling the node system for the Lamp, we have seen that it uses a material
created by connecting an Emission node to the Lamp Output node.
