The Interactive & Immersive HQ

Fulldome 101 – Part #1

[Editor’s Note: Hi all! Elburz here. The next few blog posts are a great series written by a fantastic developer and artist, Meisam Nemati. He works with a multitude of softwares and has found his passion in developing fulldome experiences with TouchDesigner. This series of blog posts will serve as a fantastic intro to fulldome experiences if you’ve never heard of them or worked with them yourself. Enjoy!]

Whether you are a developer or an A-V artist who is engaged with immersive or virtual production, you may have found “Dome” as a rising concept within the industry.  In this series of blog posts we will be covering it from scratch, discussing the tips and tricks, exploring tools and introducing TouchDesigner’s powerful workflow(s) and features to equip you with solid tools and techniques for leveraging your ability to create and produce top quality dome content. This first post dives into the high level aspects of the workflow and introduces you to domes in general.

About Dome

First let’s take a look at these amazing pieces produced in this format to better capture the main idea behind this concept.

“Dome” or “Fulldome” are theatres/cinemas that are immersive dome-shaped 360 degree screens with video projector(s) covering the whole inside area, digital planetariums being one example.

Dome production is mainly about utilizing the available 360 space to make your art spatial. This “spatial” characteristic makes Fulldome a truly immersive environment to experience imagery and sound. The unique features they offer to both artists and audience have made the concept gain popularity and resulted in the rise of Fulldome venues.

VR and 360 productions have also been on trend over the past few years (e.g. 2021 Oscar providing 360 virtual experience for audiences). What makes dome experiences special for the audience, is that unlike VR, Fulldome is a collective experience where a group of individuals can comfortably experience the content together without the need to use any gear (e.g. Oculus in VR), making Fulldome cinemas a perfect candidate for immersive movies, shows and performances.

Dome Essentials

When it comes to Fulldome production, there are many aspects and technicalities beyond just creating cool audio and visuals. This can get even more complex with the type of content, the method of design, necessity of testing the output, etc. But the most essential aspect of those technicalities is to understand how Fulldome theatre works and what type of input and output should be used in this context. Here, in this blog we have simplified the core concepts with the goal to enable you to quickly grasp the essentials and start exercising these features in TouchDesigner at the end of each episode.

Dome Projectors (Output)

Dome theatres use single or multiple projector systems. Single projector systems (Fisheye projectors, Spherical mirror, Twin Fisheye lens projection) are limited in quality and their prices soar when higher resolution is demanded. Multiple-projector system can output higher quality but needs frequent calibration and maintenance. We can safely assume that multiple projector systems are the ones that are going to be used mainly by the Fulldome theatres who promote artistic projects in order to provide higher output quality and give more freedom to the artist in terms of performance. The following are the examples of both systems for small domes.

Regardless of the projection system used, the goal is to project the imagery to the whole screen of the dome. This means that as a dome artist you are expected to not only feed inputs that are immersive, but you’re also expected to render the content correctly to fit the projection system and to cover the 360 screen. You can’t just pass your normal 16:9 content into a dome and expect a truly immersive result.

There are three main areas of content outputs we’re going to look at in the next post: photography, film, and computer generated. Each has a slightly different workflow and requires different considerations and hardware.

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Dome immersive Projection (Input)

Projection, in one of its definitions, is the technique of displaying a 3D scene into a 2D surface. Two most commonly used projection types in graphic design and gaming are “Orthographic” and “Perspective”, where the former does not depict depth (Z axis) but in the latter, depth is visualized such that it simulates human’s perception of the world. These are the kinds of projection types you normally use inside TouchDesigner when rendering 3D scenes. For the Fulldome content we use other projection types that are more complex and capture the wider portion of the scene (world).

Top left is the perspective view, the other 3 are its orthographic projections including top, front and side views.
Common Perspective projection, usual camera settings, 16:9 aspect ratio
Top, Front and Side views respectively, here orthographic views are rendered, the result is 2D image
Cube Map projection, if you fold the opened cube inwards and make a cube again, you capture the entire world
Equirectangular (Spherical) projection, result looks distorted in 2d screen but when wrapped around a sphere you capture the entire world

In the above, we have introduced two other projection types: Cube Map and Equirectangular which, unlike perspective and orthographic projection, can be used in an immersive project and later in this series, we will be exploring them in more detail. But one thing to be aware of in the above example, is that although these projection types work correctly inside the dome theatre, the content is not the best for an immersive project and to really harvest the spatial characteristics of this environment we can make our content way more profound.

This brings us to the point where we should focus on the content we create with the available techniques, mainly in TouchDesigner to make them suited for dome projection. In the third post of this series, we’ll review the projection types that work best inside the dome, and what those look like. The goal isn’t to understand the nitty gritty technical elements of every single one, but more to know what the different projection types look like and when they’re commonly used.

Wrap up

At the end of the first blog of this series, we hope you have picked up the main concept and become familiar with fulldome theatre in general. There are many aspects to discuss in the next blog posts and our goal is to provide you with what you need for creating great content that works perfectly in 360 screen, without the need to be physically present and test your content in the dome. This would open a door in your path and enable you to apply for those immersive festivals and events or undertake projects in immersive setups with a reliable workflow.

We love the 360 experience as life itself is a 360 experience, when integrating this concept with your unique skills and artistic approach and brainstorm, design and execute your project in 360 the result can be very impressive and even more unique. In the next post we’ll be exploring content that suits your fulldome project.