What are render nodes and render farms?

VizAcademy answers your questions:  “What is a render node?”, “What is a render farm?“

To find out what a render node or a render farm (which is not a farm that has been rendered! 😉 are, let’s first look at what rendering is and how it’s done.

Rendering can show how things will look when they’re built, before they are built. Autodesk 3Ds Max software is now one of the most popular pro 3D computer rendering software platforms in the world. 3Ds Max is used to render 3D models in animation, design, architectural visualisations, marketing, film, gaming, and other areas of creative output. Even the fashion and perfume industries now employ the rendering services of 3D visualizers.

OK, but …

What exactly is a render? A render is a 2D digital raster image mapped by a computer from a 3D model. This process happens in a render farm. What is a render farm? A render farm is a computer cluster designed to render photorealistic 2D images from 3D models.

During the image processing, the render farm computer optimises user-defined settings. Ambient lighting, reflection and refraction of light, textures, shapes, and other basic effects are established in the 3D model. If a modeler wants to represent, say, a scene from a cartoon, they will probably use simplified models and physical settings to achieve a less realistic effect. If the modeller wants to create something more complex, subtle, and realistic, settings will be adjusted accordingly in the render farm.   

And what is a render node?

Autodesk says: ‘Render nodes are the individual components you interconnect to use as building blocks to produce all rendering effects… Texture nodes, placement nodes, and material nodes along with their input and output connections (attributes) define all aspects of the final rendered images, from surfaces to lights and shadows.’ [1]

The 3D rendering process requires many complex mathematical calculations to be performed in and between the render nodes. The complexity of the rendering process determines the quality of the final image. The rendering procedure can take from several minutes to a whole day – depending on the number of render nodes used in the render farm.

How does a render farm work?

Nowadays, almost all moving image visuals (films, adverts, explainer videos, cartoons etc) contain 3D graphics. The film industry employs 3D artists to create SFX. ‘Avatar’ is a famous example. The film took about 40 million computer hours in render farms to create. If Avatar’s SFX renderers had used just one computer, no matter how powerful it was, the audience would still be waiting for the film to be released! This is why rendering farms are crucial.

A render farm is an array of linked computing systems that render 3D images. They are also called render nodes. Each node comprises 3D software, plug-ins and rendering modules. A rendering farm can thus increase the speed of image rendering by several thousand times.

The 3D rendering software in a rendering farm uploads a picture of reality (or animation frames) to each of its render nodes and renders them in parallel over the network. The render farm will put a frame on each render node. 10 images can be merged simultaneously on the render farm across the nodes. The processing will therefore speed up by at least 10 times. Each rendering farm node is likely way more powerful than your PC or Mac.

So now we know what a render farm is and what a render node is, let’s look at what types of render farms there are. There are two types of render farms: native and cloud (commercial).

In the commercial render farm workflow, the rendering artist uses several computers that render 3D models. Large studios may have hundreds of rendering servers. So another answer to the question ‘what is a render farm?’ is: render farms are expensive! Software, hardware, infrastructure, rack space, personnel, and electricity must all be paid for. Cloud-based commercial rendering farms can be substantially cheaper for obvious reasons.

How much does a render farm cost?

Native or cloud, rendering costs depend on various factors: the number of frames; the number of rendering node hours the task requires; the rendering tariff – the basic cost of one server and the number of servers that will be involved in the rendering assignment.

Render farm owners and managers sell their clients server uptime. The more rendering servers involved, the higher the rendering assignment costs. Prices vary from company to company and from render farm the render farm. But the average price is around $3-6 per image. Good render farms will quote – or at least enable their clients to judge the cost of a rendering assignment before commissioning them to undertake the rendering.

What are the advantages of commercial render farms?

One of the main advantages of commercial render farms is time saving. Time saving is one of the cost savings that can be derived from either hiring or acquiring a render farm (the latter is very costly). Another advantage of commercial render farms is the technical support provided for customers, which can solve problems and/or foresee them. Another benefit is simplicity. Cloud render farm providers usually have their own software. This can make the rendering farm much easier to use. Diminished risk is another advantage – and a big one. Like people, computers overheat or crash during rendering. By outsourcing a commercial render farm, this kind of problem can be avoided. Pro experts are on-hand to guarantee that the rendering will be completed and delivered according to an agreed deadline.

So that’s a bit of information for you about what render farms are and what render nodes are – and what it all means! Please ask any question you may have about rendering. We will do our best to answer them! VizAcademy. ?

Create an account to enrol for the VizAcademy® training

[1] https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-8E9EBCEC-7EA3-4B74-9DC8-0756699E2133-htm.html