8

Render Elements Panel and Rollout 129
It appends an underscore (_) and then t he name of
theelementtothebasicfilename.
For example, if the render file name is
"
C:\render\image.jpg ", when you add a Specular
render element, the default path and file
name for the rendered specular element is
"
C:\render\image_specular.jpg ".
Similarly, when you enable output to a
Combustion
workspace (CWS) file (page 3–660)
,thefilename
you assigned is the default name of the CWS file.
For example, if the render file name is
"
C:\image.jpg ", when you enable Combustion
output, the default path and file name is
"
C:\image.cws ".
Example
Here is a rendering of a fountain, against a
checkered background, and various elements.
On the right is the fully rendered fountain.
On the left, from top to bottom, are diffuse, specular,
shadow, and reflection elements.
Two more elements not directly related to the objects in
the scene, but impor tant when compositing the i mage to
other sou rces:
on the left is the background, on the right is the alpha
channel.
On the left is an atmosphere element, in this example, a
light fog on the back side of the fountain.
On the r ig ht is the Z -depth. The fog uses the depth of the
image and objects to determine its density. The Z-depth
element contains these depth values.
Compositing Rendered Elements
In general, you can composite elements using
additive composition, which is independent of the
compositing order.
Themainexceptionsarethebackgroundelement,
atmospheres, and shadows.
• Background: The background is not trimmed
against geometry, the background should be
composited
under the other elements.
• Atmosphere: Theatmosphereelementshould
be composited
over all other elements.
• Black-and-white shadows: Black-and-white
shadows should be composited over the rest of
the image (as ide from the atmosphere), to dim
color in the shadowed areas. This technique
does not take colored lighting into account.
In other words, the layers when you composite
using black-and-white shadows appear like this: