Hue Walker Bumgarner-Kirby, Multimedia Development Specialist, ARTS Lab
Hue's Beginner's Guide to Fulldome Production
Page 1 | Page 2 | Page 3This tutorial is intended to be a beginner friendly no-frills guide to creating content for Digital Fulldome Theaters. We New Mexico dome folk have had a lot of interest from students and independent artists wanting to make content for LodeStar's DomeFest as well as for UNM and ARTS Lab student work. This guide will help to explain the basics of the process. See also our tutorials for making a 5 camera rig in Maya and in After Effects.
There are two main flavors of playback systems for fulldome presentation, "real time" and "pre-rendered." Real time systems can be compared to web pages, in that they require a script or code which tells the system when, where and how to display images. (For a web page, this "code" would be the HTML.) A real time fulldome system can then take a still image, a 3D .x file, or a small .avi file and display it with instructions to move, rotate or resize on the fly, similar to the old familiar multiple slide projector shows in older planetaria. The Real Time system takes the material and slices it up and distributes it to the appropriate projectors on the fly. (The system also encompasses a very sophisticated database for display of astronomical material. Quite an accomplishment! If you want to use the Realtime method, you will need to determine if the dome you are producing for has such a system, and then you will need to gain access to instructions for scripting for that system. (LodeStar uses Sky-Skan's Digital Sky.)
The other flavor of fulldome projection is often called "pre-rendered playback" and can be compared to movie or video playback. This second type of playback requires a 30 frames per second sequence of large format images called "dome masters." This tutorial will explain "dome masters" and the basics of how to make them. (Please go to the Domefest site for specs on exactly how to make your dome masters for DomeFest. They have very detailed instructions for size, format, naming, etc. as well as specs for sound files.)
What's a Dome Master?
The image to the right is a "dome master." Notice that it is a circular image within a square. The outer edge of the circle corresponds with the lower edge or "springline" of the dome. (In this view, the bottom of the dome master is the front of the dome. Some domes may request that dome masters be configured differently, such as flipped horizontally. This example has text in the corner so the dome personnel doing the slicing can determine what you want.) The black corners will usually be discarded by the dome's display system. Fulldome playback will generally require 30 dome masters per second of playback time.
Beginners to dome production are most often confused by the multiple projectors, and the belief that they must be concerned with what goes to which projector. All you need to worry about is the dome masters. The dome's projector system will worry about the projectors. Each domed theater is custom built and they may have a different number of projectors placed at slightly different angles. The system is configured to take the dome masters and process them to their individual specifications. Your dome masters will be "sliced" into the correct number and shape of pieces for the projectors, and you don't have to have anything to do with that! The dome masters are the common ground between the various domes.
(Note: the one exception is that domes may be tilted to different angles... LodeStar is tilted forward 20%... so you may need to make dome masters designed for a particular tilt if you need the appearance of a level horizon. Note that the dome master above has a bit of earth visible along the lower edge of the circle (the front,) while the buidings at the top (back) are cut off at the bottom. This is due to a -20% tilt in the production of the dome master to compensate for the tilt of the dome. Some stitching software will allow you to adjust the tilt so you don't have to re-render your dome masters for a differently tilted dome, but you need to plan ahead and render below the center line of the F, B, L, R cameras. This will make sense after you read the Maya camera tutorial, in which you are shown how to render only the top half of the front, back, left and right views.)