Full Dome: What is it and what can we do with it? Part One

For background, you might consider reading the Wikipedia article on Full Dome.
Wikipedia also lists Reuben H. Fleet Science Center as an innovator in the historical  section in 1973.
This Wiki page describes  Voyage to the Outer Planets,  Our first presentation, a multimedia show which combined film, custom made planetarium projection devices and our star projector.

Full Dome is a video image that cover the entire dome. There are several ways of creating this imagery.
One way is using standard computer graphic tools such as 3D Studio Max, Maya, Bryce, Blender or the other software packages out there. The images must be specially created to fill the dome – the target media is NOT a flat screen, but the inside of a dome. And yet we create it ON a flat screen. The creator of Full dome sequences must output the video as a “Dome Master”. This series of 30 still frames per SECOND is saved as PNG format images.  As it will be filling a dome you must make some mental interpretations to view it on a flat screen, until you can see it in its intended locale: inside a hemisphere. Wrap you mind around the following concepts to understand…

dome filling template

Note that the top of the image is UPSIDE DOWN when viewed on the flat screen you are probably seeing this on…

West is on the right side, but rotated 90 degrees, and the East is on the left side, but rotated 90 degrees in the OTHER direction. The Northern direction is upside down.
However, imagine projecting this image on the inside of a dome, not a flat screen like your computer screen, and then imagine you can get inside that dome, sit in the center and rotate your whole body to look at every angle, it would be correct.
The North would be projected not upside down, but on one quarter of the dome, directly opposite of the South. Behind you if you are facing South.

Here is a real image, if you are confused, this should help.

180 degree fish eye type lens

A “Fish Eye Lens”?

Using the before mentioned 3D software, the stills are rendered using a virtual fish eye lens. A real fish eye lens captures light from 180 degrees around the camera.
The virtual fish eye uses ray tracing to trace the rays of light from the light source, to the objects in the scene,  and then to the “camera”. Depending on its setting, you can render images for a small flat screen, or for the larger fulldome format.

Fish Eye Lens Diagram

A fish in still water can see the world above the water through a circular window overhead. This is an optical phenomenon known as “Snell’s Window,” and it happens to not only fish eyes.
If you lie in water and look up the water surface, you will see just the same thing: By the action of the refraction of light,
a 180-degree view of the world above the water condensed into a cone angle of about 97.2 degrees in water with refractive index 1.33.

The other method of creating Fulldome content is immediate and does not rely on rendering. Borrowing from the gaming industry and their increasingly powerful graphics cards, a virtual world can be created that will allow the camera to move around it in real time.
If you were playing a video game, you would be likely blasting your enemies and traveling across a landscape, dungeon or spacecraft.
In a more educational use such as we will be presenting, the same sort of software will allow the operator to take the audience through a 3D model of the Solar System, or out to the distant reachs of the Galaxy. But the system will not be restricted to astronomy.
Models exist also of molecules, biological structures, geology and many other scientific disciplines. As time goes on we intend to add more and more uses to this system.
It is a tool to reach the future with, and like a tool, can be used for any purpose.

Would you like to know more?
Download free or inexpensive software that will allow you to create your own virtual worlds and explore or create images of them.
These are all Open Source, and available in several computer formats.
Blender is FREE and pretty friendly. But DO read the manual!

Perhaps you would like to travel through space? Try Celestia. This FREE software creates a model of the Solar System and places beyond in your computer. You can even render from this fine open source software.

Additional pieces for Celestia add spacecraft from history and science fiction.

Both of the above software suites have extensive users groups, and I must refer you to them for assistance.

Partiview is outstanding as well, another FREE product, this one is from the Hayden Planetarium

If these are too scientifically oriented for you, try Bryce. This fine software gives you the ability to create your own worlds and it has an excellent GUI, or Graphic User Interface. I find it is an excellent piece of software for introducing the concepts of 3D.
They also sell objects you can add to your creations, but the basic software is around $20.00.


3 Responses

  1. Sounds like this has limitless possibilities. Can’t wait to see it all in action!

  2. The second image taken from the Dark production. Why do you call it a “50 degree fish eye type lens”. It is actually a 180 degree fisheye extracted from the 360×180 video capture from a LadyBug-3 camera.

    • Thank you Paul. I believe it was a typo, and I have changed it to a 180 fish eye lens. Is this your image, and should I attribute it to you ? John

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