2008

By default, there's no ambient light in a scene. If you examine the darkest
shadows on your model with the default ambient light setting, you cannot
make out the surface because it's unlit by any light. Shadows in your scene
will not appear any darker than the ambient light color, which is why you
usually keep ambient light set to black (or a very dark color).
If you use photometric lights and a
radiosity solution on page 5976 , ambient
light is accurately calculated. The other advanced lighting option,
light tracing
on page 5963 , also generates ambient lighting.
If you use standard lights, a good lighting test is to set your ambient lighting
to black (the default), set up all your lights, and then decide at the end if you
need to increase the ambient light.
Animated Texture
An animated texture is a material whose properties change over time. One
example of this is assigning a multi-frame bitmap (for example, an AVI file or
an IFL image-file sequence) as a map.
Animated textures can also be materials with keyframed parameters. In
addition, in the context of particle systems, a material that uses the
Particle
Age map
on page 5727 or the Particle MBlur map on page 5729 is considered to
be animated.
In general, when applying an animated texture to particles in Particle Flow,
be sure incorporate it in a
Material Dynamic operator on page 2846 .
Animation
Animation is based on a principle of human vision. If you view a series of
related still images in quick succession, your brain perceives them as
continuous motion. Each image is called a frame.
Historically, the major difficulty in creating animations has been that the
animator must produce a large number of frames. Depending on the quality
you want, one minute of animation might require between 720 and 1800
separate still images. Creating images by hand is a big job. That's where
keyframing comes in.
Most of the frames in an animation are routine, incremental changes from
the previous frame directed toward some predefined goal. Early animation
studios quickly realized they could increase the productivity of their master
Glossary | 7711