Graphics Reference
In-Depth Information
make the surface completely reflective on the perpendicular surfaces, and that amount will taper as the sur-
face faces the camera.
Figure 3-6
displays this effect in action.
The Reflection Color option allows the reflections to take on a tint. When this option is set to white, re-
flections appear with coloration identical to that of the actual reflected object(s). Adding color to reflections
tints them so that they appear less pure. Usually a good starting point for this setting is the same value as
Diffuse Color with some white added in (lightened color). Varying levels from the diffuse color to white will
work best for most objects, but setting Reflection Color to a color that is contrasting to Diffuse Color can
produce some interesting effects. Reflections can be set to reflect everything or just an image-based envir-
onment. This is controlled through the Reflection Type option. Although full-scene reflections take longer
to render, they give a more accurate and realistic effect—and with the speed of most modern computers,
reflections calculate quickly enough to use this better-quality setting on pretty much every image.
Figure 3-6:
The Fresnel setting set to 0% (left), 50% (center), and 100% (right)
The Roughness and Anisotropy options control the sharpness and regularity of reflections, respectively.
Roughness settings at low values are associated with a smooth surface that will evenly reflect the environ-
ment. A higher Roughness setting decreases the legibility of reflected objects and causes them to blur. Blur-
riness increases as the reflected object gets farther from the surface. When the Blurry Reflection check box
is selected, the Reflection Rays field will become active. Lower settings in this field make rougher blurs that
render more quickly, while higher settings increase the quality of the blur at the expense of render time. An-
isotropy is the effect of stretched reflections. There are several ways to achieve this, and different techniques
will be discussed later chapter. Generally, setting the Anisotropy option to positive percentages tightens the
reflections on one axis, and setting the value to negative percentages causes the effect to occur perpendicu-
lar to a positive setting. This setting can be used to achieve anything from simple brushed metal to complex
effects such as carbon fiber and machined metal.
Blurry Reflections
Roughness will affect the reflection only if the Blurry Reflection check box is marked, but roughness
will always affect specular reflections.
The final setting in the BRDF section is Clearcoat Amount. This setting will add a small amount of clear
reflections that increase in intensity as the surface becomes more perpendicular to the camera (Fresnel ef-
fect). This adds a layered effect to the surface and works particularly well in conjunction with blurred or
anisotropic reflections. A good real-world example of this is car paint. The initial coat of paint often has
softly blurred reflections and contains the color information of the paint. On top of the base coat is a thin
