What is renderfarm

A render farm is a computer cluster built to render computer-generated imagery (CGI), typically for film and television visual effects, using off-line batch processing. This is different from a render wall, which is a networked, tiled display used for real-time rendering[1]. The rendering of images is a highly parallelizable activity, as each frame usually can be calculated independently of the others, with the main communication between processors being the upload of the initial source material, such as models and textures, and the download of the finished images.

Over the decades, advances in computer power would allow an image to take less time to render. However, the increased computation is instead used to meet demands to achieve state-of-the-art image quality. While simple images can be produced rapidly, more realistic and complicated higher-resolution images can now be produced in more reasonable amounts of time. The time spent producing images can be limited by production time-lines and deadlines, and the desire to create high-quality work drives the need for increased computing power, rather than simply wanting the same images created faster.

To manage large farms, one must introduce a queue manager that automatically distributes processes to the many processors. Each "process" could be the rendering of one full image, a few images, or even a sub-section (or tile) of an image. The software is typically a client–server package that facilitates communication between the processors and the queue manager, although some queues have no central manager. Some common features of queue managers are: re-prioritization of the queue, management of software licenses, and algorithms to best optimize throughput based on various types of hardware in the farm. Software licensing handled by a queue manager might involve dynamic allocation of licenses to available CPU's or even cores within CPU's. A tongue-in-cheek job title for systems engineers who work primarily in the maintenance and monitoring of a render farm is a render wrangler to further the "farm" theme. This job title can be seen in film credits.

Recent research has explored the feasibility of reprogramming modern video cards to do rendering in the card's hardware.

ref: http://en.wikipedia.org/wiki/Render_farm