Batch Rendering of Computer Animated Sequences


Principal Investigator

Stuart Ramsden

Australian Centre for the Arts and Technology, ITA

The aim of this project is to enable the rendering of animated sequences which would be difficult or infeasible under any other scheme. Currently, rendering occurs on ACAT's lab of SGI Indy workstations, in a render farm arrangement. When workstations become idle, render jobs are automatically started and continue until the next period of activity. Whilst this is a good mechanism which extracts the most CPU from any available workstation, its effectiveness is entirely determined by the duty cycle of the interactive load. Towards the end of a teaching semester, the ACAT workstations are used interactively for longer and longer periods, leaving little time for rendering. Also, the memory available for rendering is limited to that of the workstations, sometimes as little as 20Mb, with little relief coming from virtual memory, as the raytrace algorithm causes the computer to thrash while it pages the database in and out of memory. This places severe restrictions on both the image quality (anti-aliased raytraced images takes approximately 6 times longer to render) and scene complexity. The speed and memory of the Power Challenge make it ideally suited to this task, and this project would enable the production of sequences that are currently beyond the computational abilities of ACAT workstations.  


v57 - PC



What are the results to date and the future of the work?

Towards the end of 1996, for a brief period (less than 2 weeks) we were able to use the Power Challenge to render over 16 minutes of ray-traced animation, utilising over 360hrs of CPU in the process. Due to the nature of the requirement for large amounts of computation resources in a very short time span, (the final stage of animation production) it would have been difficult, if not impossible, to carry out the work in any other way. The project continues to be an important part of the production of high quality animation by students and staff at ACAT.

What computational techniques are used?

The production renderer used is 'Mantra' a product from SideFX Inc. and part of the commercial animation package PRISMS. It uses raytracing to calculate its imagery, and




whilst efficient in what it does, this process can become very CPU intensive, especially as scene complexity grows. We have one license for a 2 processor version of the software, which would take advantage of the multi processor architecture of the Power Challenge.

The SGI Power Challenge is ideally suited to this task, with its fast floating point performance, multi processor capability and large memory capacity.


Chronopolis - ACAT Performance Night Semester 2 1996


- Appendix A