2008

Additive Opacity
Sphere on the right uses additive opacity.
Additive opacity brightens the colors behind the material by adding the
material's colors to the background colors. Additive opacity is good for special
effects such as light beams or smoke. You specify the use of additive opacity
on the
Extended Parameters rollout on page 5312 .
Additive Opacity and the Alpha Channel
By default, additive opacity does not generate an alpha value. In other words,
the alpha value is zero, indicating no transparency. This gives correct results
with backgrounds in renderings, but if you want to composite objects with
additive opacity using video post or a compositing program, you might want
to have additive opacity render with transparency. To do so, add the following
line to the [Renderer] section of the 3dsmax.ini file, and then restart 3ds Max:
AlphaOutOnAdditive=1
To revert to the default method of rendering additive opacity, in the 3dsmax.ini
file, change the value of AlphaOutOnAdditive back to 0 (zero), and then restart
3ds Max.
7706 | Glossary