View Full Version : Need Coverage and BgColor render buffer outputs needed for professional production.

02-26-2010, 12:08 PM
In our professional work, LW lacks these render buffer channels that would increase efficiency and power of compositing with Fusion or other programs.

The Fusion 6 manual describes the function of these channels:


This option enables rendering of the coverage channel. The coverage channel contains information about which pixels in the z-buffer provide coverage (are overlapping with other objects). This helps tools that use the Z-buffer to provide a small degree of antialiasing. The value of the pixels in this channel indicate as a percentage how much of the pixel is composed of the foreground object.


This option enables rendering of the BgColor channel. This channel contains the color values from objects behind the pixels described in the coverage channel.

02-26-2010, 01:10 PM
There seems to be a lot of renderers that don't generate these properly. I've actually thought about getting these out of LW via a plugin for some time and have yet to find a decent solution that covers all cases.

A decent work around is to render at double res (with a lower AA), apply the 3D effects in Fusion and then scale down.
It does increase the time required for a comp, but leads to decent enough results and even has some advantages over the coverage buffer (which basically fails if a pixel consists of samples from more than two surfaces, or more than a single surface and the background).