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How Centropolis FX Creates Visual Effects


The Technology
Drew McKeen standing next to the SGI Onyx machines
Drew McKeen standing next to the SGI Onyx machines

Digital visual effects at the Hollywood level require an incredible technology infrastructure that includes both hardware and software. The machine room at CFX shows just how extensive the hardware investment is. The team needs massive amounts of hardware for four reasons:

  • The scanned film and the different layers that the team creates require gigantic amounts of disk space. A single frame of a film, once scanned and stored on a disk, consumes on the order of 10 megabytes of disk space. All of the shots of "The Patriot" together consume 1.6 terabytes (trillions of bytes) of disk space.
  • Individual artists need high-end desktop machines to work on and render their individual models and layers.
  • Rendering requires massive CPU resources. To render any animated 3-D figure or any effect like water or smoke, the CPU must generate millions of polygons, lines, points, etc and then light them correctly. And it must do this over and over again for each frame of the shot! For example, in "The Patriot" certain scenes incorporate hundreds of soldiers as well as things like boats, tents, flags, and so on. Each one moves independently, according to mathematical models expressed in the form of thousands or millions of pixels that are each calculated specifically.
  • Compositing - Compositing combines dozens of layers into a single shot. Because of the resolution involved -- millions of pixels and tens of millions of bytes per frame -- and the layering, both the CPU workload and the storage requirements are immense.

All of this means that the machine room at CFX is an amazing place!

Desktop machines are stored in the machine room to make maintenance and upgrades easier.
Desktop machines are stored in the machine room to make maintenance and upgrades easier.
The Linux render farm formed from standard PC desktop units
The Linux render farm formed from standard PC desktop units
Some of the many hard disks that form the online disk space available at CFX
Some of the many hard disks that form the online disk space available at CFX

This quick video walk-through of the machine room shows you the scope of the equipment required for the team at CFX to do its work.

The workhorses at CFX are a collection of SGI Onyx machines. These machines contain multiple processors and specialized graphics pipelines that speed the rendering and compositing tasks. Typically, a compositing artist will use an Onyx as his or her "desktop" machine, and other artists will run background rendering tasks on them as well. There is also a Linux render farm formed out of dozens of PC desktop machines. These machines work together to subdivide and execute rendering tasks.