Everyone reads articles about the immense number of processor hours required to create visual effects and animations for the latest films and TV shows. For example, render times totaled 40 million hours for Monsters vs. Aliens, 30 million hours for Madagascar: Escape 2 Africa, and 6.6 million hours for Revenge of the Sith.
A good render time for television visual effects is anywhere between 30 minutes to one hour per frame, while multiple hours per frame is common for feature films. Some of the IMAX resolution frames required for Devastator, a character in Transformers 2: Revenge of the Fallen, took up to 72 hours per frame. How do studios get around this? They use render farms, which are banks of machines with the express purpose of rendering finished frames. In addition to the systems that animators use, render farms simultaneously use many dedicated processors for rendering. For instance, Industrial Light and Magic had a render farm with 5,700 processor cores (and 2,000 cores in their artists' machines) when Transformers 2 was produced. Even a small facility with only a dozen animators is likely to have more than a hundred processor cores at their disposal.
Do You Need A Render Farm?
Use of render farms isn't and shouldn't be just restricted to large studios and 3D artists. Smaller studios have their own render farms and many freelance artists have them as well. Compositors and freelance motion-graphics artists can also make use of them. Some editing systems support the use of additional machines called render nodes to accelerate rendering, and this type of setup can be extended to architectural visualization and even digital audio workstations.
If you are working as a freelance artist in the above-mentioned media, toying with the idea, or doing so as a hobbyist, then building even a small farm will greatly increase your productivity compared to working on a single workstation. Studios can even use this piece as a reference for building new render farms, as we're going to address scaling, power, and cooling issues.
If you're looking at buying a new machine and are thinking of spending big bucks to get a bleeding-edge system, you might want to step back and consider whether it would be more effective to buy the latest and greatest workstation or to spend less by investing in a few additional systems to be used as dedicated render nodes.
Most 3D software and compositing applications include network rendering capabilities, and many also have some form of a network rendering controller. So, the additional nodes can be managed from your workstation, making it possible to run them as headless systems with no mouse, keyboard, or monitor. Adding a Virtual Network Computing (VNC) client to each node allows you to remotely manage the nodes without the additional expense associated with adding a multi-channel system keyboard, video, and mouse (KVM) switch for separate access to each.
Buying The Farm
There are three ways to approach acquiring systems for a render farm: building your own, having a builder make them for you, or buying pre-built boxes. Each approach has its own set of advantages and disadvantages, which we discuss below. Each approach also involves progressively higher price tiers, which range from cheap to insane.
A useful tip is to make sure the processors in your render farm are the same as the processors in your workstation, as there may be differences in rendering between processor architectures, which could mean small differences in your final rendered frames. However, these potential compatibility problems are today the exception rather than the rule, but it is still something to be cautious about. For the purposes of this article, assume that we're talking about Intel-based render nodes, although they could just as easily center on AMD CPUs.