
March 8, 2011 - Computer-generated imagery can
be lovingly and photo-realistically rendered. The more
realistic the scene that is generated, the longer it usuallly
takes. For visual special effects in movies, this can be
minutes to hours per frame. However at the other extreme,
such imagery can be created so quickly that they can represent
virtual environments that a user can interact with. When this
is done so fast that the user doesn't notice any lag, you have
real-time graphics. This is what the video game
industry is built on and what allows us to navigate through
simulations of the known universe in the Gates Planetarium.
In 2001, I started work at DMNS in the SciViz group, and was
tasked to help build the software that would let us fly through the
Solar System, and eventually the rest of the Universe. At the
time, there was nothing else out there that could do what we wanted
the Gates Planetarium to be capable of. We had to develop the
software ourselves.
Luckily at the start of the 21st century, graphics hardware had
progressed to the point where realistic full-sized flight
simulators could be built (often for the military) using multiple
computer projectors and banks of specialized graphics
supercomputers. The modern digital planetarium would take
advantage of these advances in simulation, in how imagery was
generated and projected, as well as how that imagery was generated
to begin with.
The new Gates Planetarium would have stadium-style seats, with
everyone looking in the same forward direction. The dome and
the seats would be raked (or angled) by 25 degrees, to give a more
immersive feel. Eleven massive computer projectors from the
Barco company would be aimed at the inside of the hemispherical
display. Each would tile one-eleventh of the dome's
surface. When properly aligned, the eleven fragment images
would tile together to give one (more or less) seamless fulldome
image.
The visuals sent to the projectors originated from an Onyx 3800
graphics supercomputer, made by Silicon Graphics, Inc. (SGI).
At the time, purchasing one of these behemoths was the only way to
create our virtual reality simulation of the known universe with
the Cosmic Atlas software, which was developed in-house at
DMNS by the SciViz team. Chief developer and head genius on
this project was Nigel Jenkins, a brilliant graphics programmer,
lured from England. I worked on the scientific programming --
ensuring that each star, planet, and moon were in their correct
place. Nigel wrapped it all together into an effective suite
of visualization code, all the more impressive when you consider
how few people were actually responsible for writing it.

By the time the Gates Planetarium opened in the summer of 2003,
Cosmic Atlas was a usable simulation platform, not only in
the planetarium but out in the Space Odyssey exhibit, where it
drove the Orbits Table. It also had a show production
interface that allowed the SciViz team to create the Cosmic
Journey show which premiered in the digital Gates Planetarium
when it re-opened.

...
Since then, the computer graphics industry, driven by Moore's
Law, has evolved by leaps and bounds, and the Gates Planetarium has
changed with the times as well. The SGI Onyx is no longer in
our computer room, having been replaced by a bank of smaller,
sleeker, and faster machines. Graphics processors now
available from companies like Nvidia and ATI provide more
visualization crunching power than any of the "graphics pipes" from
our original Onyx. Even Cosmic Atlas has gone away,
and replaced with the much more versatile Uniview that
runs on our planetarium visualization PC clusters as well as the
computer driving the Orbits Table in Space Odyssey.

But the original digital planetarium legacy remains. The
Cosmic Journey show has gone through four iterations now,
incorporating revised content with each new edition. There
are still surviving sequences within that show that were created
with the old Cosmic Atlas software. Our experience
with real-time software development has resulted in new research,
collaborations, projects, and funding opportunities, from ALIVE to
the Worldviews Network, and countless other projects in
between. That's quite an impressive record for something that
we started building more than ten years ago on computer hardware
that would be quite antiquated compared to what we have today.