DreamWorks, the animation company behind Shrek 2, has raised the curtain on the technology which made the blockbuster possible.

Linux played a key role in creating the film, which had its London premiere yesterday and enjoyed the biggest opening weekend ever for an animated film on its release in the US.

DreamWorks needed as much computing power as possible to implement newly developed computer graphics techniques.

These included subsurface scattering for more realistic skin, global illumination for more realistic lighting, better looking hair and larger crowd scenes with more complex characters than seen in the original Shrek.

Over 330 Hewlett Packard workstations running Linux were used by digital artists to create the animations.

The xw8000 workstation featured Red Hat Linux 7.2, dual-Intel Xeon 2.4GHz processors, nVidia Quadro 4 XGL graphics cards, 2GB Ram and dual monitors.

The hefty provision of Ram allowed animators to store more frames of animation, while the faster speed of the processors allowed recalculated frames to have more detailed geometry, which helps the animators to pre-visualise and make decisions before rendering.

At the back end, the Shrek 2 render farm was comprised of 347 LP-1000 1.2GHz P3 dual processor servers with 2GB of Ram and 433 ProLiant DL360 2.8GHz P4 dual processor servers with 4GB of Ram.

Some portions of the film were rendered remotely at HP Labs in Palo Alto.

Shrek 2 website