What is 3D Rendering & What Are Render Farms?

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This is a guest post from the team at GarageFarm.NET.

Many use the term 3D rendering to describe the entire process of creating an image using digital 3D tools. Doing so leads to misunderstandings regarding an online render farm as a production service for 3D. We’ve certainly had our share of such inquiries at GarageFarm.NET.

We understand since, in a way, rendering in 3D is the process in which a project becomes an actual image from an assortment of geometry, virtual lights, and image textures. However, this is only a stage of the production process behind creating the final work. 

3D rendering relates only to converting a 3D scene, an assembly of models with surface properties that simulate real-world materials in three-dimensional virtual space into a two-dimensional image or sequence of images.

An Overview of a 3D Rendering Production Pipeline

To put things into perspective, let’s take a look at what goes into creating this render:

An example 3D render.
An example 3D render.

Let’s assume a team of 3D specialists created this image from scratch for a client.

The 3D modeller will have created the geometry in the scene.

The completed main 3d models to be used in the scene
The completed main 3D models to be used in the scene.

The 3D texture artist will have taken the models and created image maps that would drive shader parameters for the models.

Shaders simulate physical surfaces such as wood, skin metal, and glass and are also used to create non-physical effects such as making the models appear as though they’ve been hand-drawn, for example. 

models with shaders and textures applied
The models with shaders and textures applied. 

The 3D layout artist will have arranged all the models in front of a virtual camera and lit them in a way that would fit a client or director’s brief. 

final composition angle1
The final composition.
final 3D render composition from another angle
The final composition viewed from another angle.

Someone who specialised in actual rendering would only make adjustments to the render settings of a project for efficiency – managing a precarious balance of the speed of a render, and the fidelity of the resulting image. A crucial step in creating 3D renders, but evidently, by no means the only step. 

3D rendering settings
The render settings used in the 3D rendering program.

As you can imagine, 3D renders with elaborate environments, hi-poly characters and props could take a sizeable amount of time, to say nothing about the time it would take for a computer to complete the final 3D rendered images.

A graphic depicting a speculated render time for a frame.
A graphic depicting a speculated render time for a frame.

This is where render farms come in.

How Render Farms Work

Simply put, a render farm is a computer system connected to a network that can receive instructions to render 3D projects. The main allure of using a render farm is that it dramatically shortens production time.

A simplified graph illustrating the main components of a render farm.
A simplified graph illustrating the main components of a render farm.

Let’s bring back our example from earlier to elucidate better:

Let’s say our client was delighted by the image we sent her, and now she would like some camera movement showcasing more of the scene.

Of all the specialists that worked on the project, perhaps only the layout artist would need to return and animate the camera before the rendering specialist optimises settings for an animation. It should take no time at all, right? 

Not quite.

Imagine it took 10 minutes to render the still image at its current quality. We’ve now moved from that single frame to an entire sequence of frames-say, a hundred frames.

That means if we were to render everything on a single computer, that would take 16.5 hours! On top of that, the workstation is now out of commission since it will be rendering all those frames. 

A simplified graph illustrating the rendering process of a render farm
A simplified graph illustrating the rendering process of a render farm.

But on a render farm, when instructed to do so, every computer or “node” in a render farm can open a 3D project, render an image from that project and save that render in a centralised folder. 

So if we had a render farm 50 nodes strong, and the nodes could each render one frame simultaneously, our staggering 100 hundred hours becomes a bearable 2 hours.

Of course, maintaining a render farm is quite the additional cost if we factor in energy consumption, maintenance, and IT management. A viable alternative is sending your projects to a cloud-based third-party online render farm.

A simplified graph illustrating a render farm's cloud infrastructure, from the workstation, to render management, to file server, to render nodes, and then to data storage and back
 A simplified graph illustrating a render farm’s infrastructure.

Online render farms host many nodes and usually provide a plugin for your 3D program that facilitates the transfer of your project to the service and the resulting frames back to your local machine. Some even have a dedicated support team you can communicate with in real-time to ensure everything goes smoothly. 

Suppose we had rendered our hypothetical scene on an online render farm. In that case, we might have been able to get all of our frames in 2 hours or even less – saving much-needed time and sanity while allowing us to continue working on other projects. Ultimately, we decided to take our example scene and put it through our online render farm. 

We rendered a 210-frame-long sequence. Here is the resulting time and cost we got on our browser-based job management app.

A clip of our web-based manager app for users
A clip of our web-based manager app for users. The highlighted row represents the final iteration of our scene.
The start time and cost of our render job. 
The start time and cost of our render job. 
render logs for the render job
Our render logs for the render job. “Time Good” represents the elapsed time for the successful render of the frames listed on the far left.

As we can see from the log above, the last frame finished rendering at 6:51:45 PM. The project started at 6:16:25 PM. Thanks to the render farm, we rendered our entire sequence in 35 minutes and 20 seconds.

On a single machine with the same specifications as the render farm’s nodes, that would have been over 26 hours (using the average time per frame indicated at the bottom of the render logs). 

Thanks to online render farms, we would have hypothetically been able to get back to our client with an entire animation in the time it would take to have a coffee break!

Here is a sample sequence we rendered through a render farm.

Hopefully, this illustrates, in essence, the usefulness of a render farm and how it can mean the difference between a successful project for a client and a missed deadline.

To learn more about render farms in-depth, have a look at this explainer video.

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