Issue: Volume: 24 Issue: 1 (January 2001)


By George Maestri

Discreet's Combustion is a robust 3D compositing package for Windows NT and the Macintosh that supports compositing, painting, motion tracking, and keying, all in one package. It's like a little sibling to Discreet's popular Flame, Flint, and Inferno SGI-based digital-effects toolsets that brings true high-end compositing to the desktop.

Combustion supports Adobe Premiere and After Effects plug-ins, which you can copy to Combustion's plug-in directory after you install the program. Navigating the software's interface is fairly straightforward, with ports for viewing footage at the top of the screen, playback controls in the middle, and user controls toward the bottom.

Bringing footage into the package is easy. Combustion supports about 20 standard image file formats, including TIF, Targa, QuickTime, AVI, and Cineon (for film work). The two most interesting formats are RLA and RPF, both of which can encode 3D data in an image file. This allows Combustion to extract such data as the Z depth of each pixel, as well as geometry, motion, and camera data, thereby simplifying the compositing process and making your results more accurate.
Images in Combustion can be placed in 3D space. Lighting also can be added to create shadows.

When loaded, images are stored in the program's Work space, which can contain one or more composites that can be layered together to create more complex scenes. Interaction is fast. Discreet has included a RAM player for faster previews, as well as a draft mode that degrades the quality of the image so that effects render quickly, enabling you to work faster.

Most compositing packages work in 2D space, whereby each element is simply layered on top of the next. Combustion can work well in this way, but its real strength is that it's a true 3D compositor. You can position each element along not only the X and Y axes, but also the Z axis to provide true depth. This is a much more flexible way of working because it enables you to easily animate elements from front to back in an image. Because each element has depth, it is easy in Combustion to simulate real-world effects such as perspective, as well as perform any number of cool 3D tricks, such as spinning elements in space.

Combustion also includes lights and cameras. The cameras provide a way to view your work from different angles, and you can use them to simulate real-world camera effects such as rack focus. The lights work much as they do in 3D packages, and they can be used to cast shadows through one bitmap onto another.

Like most compositing programs, Combustion comes with a large array of filters and effects that can be applied to clips and elements. These include standard blur effects and color correction filters, among others. Of special interest are the ones that take advantage of 3D data in image files, such as depth of field and fog.

Combustion includes Discreet's keyer, a tool that enables you to matte out specific colors for applications such as green or bluescreen. The keyer is robust and enables you to shrink, blur, or erode the edges of a matte. It also can manipulate the histogram or color-correct an image to make a matte pop more.

In addition to these tools, Combustion comes with a built-in paint package that is useful when developing special effects. Because Combustion brush strokes can be animated, they can be used for paint effects such as laser blasts. Brushes also can take their color from other parts of a composite. This is great for jobs such as wire removal, in that you can paint out the wires in an image by grabbing pixels from another frame.

Another good special-effects tool is the motion tracker, which captures the motion of an on-screen feature, such as the side of a bus. The tracker then applies that stored motion to a second element, such as a sign, so that the two appear to be "locked" together. The software supports tracking of unlimited points, which can be applied to objects in a number of ways.

I found the motion tracking to be accurate, which makes Combustion good for high-end work. Combustion also can export motion-tracking data into all the higher-end Discreet systems, including Flame, Flint, and Inferno. This should enable studios to off load some of the compositing work from high-end machines to less-expensive Com bustion-based workstations.

I don't normally gush over software, but Discreet has pretty much nailed this one on the head. I plan to use this package extensively in the future. Combustion brings much of the power of Discreet's high-end solutions to the desktop, making it one of the most complete desktop compositors I've seen.

George Maestri is a writer and animator living in Los Angeles.

Price: $2995
Minimum system requirements: Macintosh: 200MHz PowerPC; MacOS 8.1; 256MB of RAM; 20MB of disk space; QuickTime 3.0. Windows: 200MHz Intel-compatible processor; Windows 95/98/NT/2000; 256MB of RAM; 20MB of disk space