Unreal Film-maker of Martian Reality
Interview with Daniel Maas
Daniel Maas is the driver behind the stunningly realistic animations that depict the current Mars Exploration Rovers. His renderings have brought a standard to visualization in planetary exploration not previously possible. Astrobiology Magazine had the opportunity to talk with Maas about how his project came to life.
Astrobiology Magazine (AM): Do you recall the first time you drew up the storyboards for your initial Mars simulations? Would that have been for Mars Polar Lander, or the scrubbed 2001 series? What was your first reaction to the chance to do those animations?
|Spirit preparing to investigate a rock
Credit: Maas/Cornell/ NASA/ JPL
Daniel Maas (DM): I first started working on NASA missions at Cornell University with Prof. Steve Squyres, who is now the Principal Investigator for MER. I showed him my personal animation projects and asked if he could find an opportunity for me to create animation for NASA.
I had always wanted to try applying Hollywood techniques to real-life space exploration. I think reality is often more interesting than fiction, especially in the case of missions like MER. The complicated sequence of events from launch to landing is just as dramatic as any sci-fi action scene, and deserves the same visual treatment.
Steve hired me to create a launch-to-landing animation of the 2001 Mars Lander. In fact I created a full five minutes of animation which had to be thrown out when the mission was cancelled in 1999. But this was a blessing in disguise since a lot of our work up to that point carried over to MER. For instance, the launch rocket was still a Delta II, so I didn't have to change much there.
Recently we heard that the 2001 lander will be reincarnated as the Phoenix mission. I'll soon be taking the animation I created years ago for 2001 and updating it for Phoenix.
See gallery of Spirit's Sol images and slideshow
AM: About how long did you have to research the mission profile before actually having the first rough-cut?
|Mars Exploration Rover with main instruments indicated by location on the unfurled instrument after stand-up.
DM: I started drawing up storyboards almost immediately. Steve Squyres gave me a basic outline and provided some images of the lander. We filled in most of the details later. For example, we knew the upper stage of the Delta rocket was spin-stabilized, but we didn't know the exact rotation rate or the mechanics of the yo-yo de-spin system (the two counterweights that fly off the spacecraft to reduce its angular momentum).
Steve did a great job finding the right people to answer technical questions like this. In the case of the Delta rocket, I spoke directly with Boeing engineers to learn the details of the systems and make it all look right. I also worked extensively with the MER engineers at JPL on the landing system and the rover itself.
AM: In doing the 12,000 frames for the eight minute video, how much of that artwork depends on blended scenes and how much has to be done from original plans in 3-dimensions?
DM: Absolutely every frame in the video is an original 3D creation. Some of the launch and low-altitute earth shots made use of photos for background images, but there is no live-action footage in the animation.
AM: When NASA's Associate Administrator did a June 2003 press conference with Steve Squyres, he commented then in jest something to the effect "Everytime I see that Cornell video, it seems like there are too many moving parts" to the mission. While he was underscoring the difficulty of landing on Mars, from the animator's viewpoint, could you outline the details that you had to gather about the rovers and mission before starting?
DM: Since we were aiming for total visual realism, I had to model every aspect of the rover and spacecraft. I built a model of the Delta rocket and launch pads 17A/B at Cape Canaveral based on many reference photographs. I modeled the upper stages of the Delta and the MER cruise stage based on photos and CAD drawings [computer-aided design].
The rover is the most complex model of them all (and by far the most intricate model I've made to date). It took about 2 months of pouring over drawings and photos to construct an accurate model. I included every detail I could find, even the serial numbers printed on the various instruments and all major wires and screws. If you look at actual space hardware, there are wires and bolts all over the place, so it was necessary to model all of them to generate photo-realistic renderings.
|Airbag descent towards the surface of Mars
I am often asked why I don't simply use CAD models of the hardware. It's because a model that is useful for engineering purposes won't necessarily help you generate pretty pictures. A model for rendering must have a uniform level of detail so that it looks good but doesn't choke the animation software. Sometimes engineering models have way too much or too little detail. Also, sufaces made from different materials like plastic and metal must be separated and assigned visual appearances. By the time you "massage" a CAD model into visual shape, it takes about as much time as starting from scratch.
|First sunset on Mars, where each day, or sol, is slightly longer than an Earth-day
I also had to learn about the dynamics of the mission, especially the physics of descent and landing. For reasons of editorial control I animated most of the motions by hand, but I used physics simulations as a guide. I chose manual animation because it's hard to get a physics simulation to give you the exact result you want - e.g. if you need the airbags to bounce in a particular spot, it's much easier to specify that by hand.
Steve Squyres provided most of the details for post-landing operations, like the sequencing of ther rover's deployment, and its driving methods. For example, we made sure to include a shot of the rover "arc driving," where it drives with the wheels turned to avoid an obstacle.
AM: The commitment you had to the mission fidelity seems remarkable, all the way down to correct star locations from NASA astronomy databases. What was your complete timeline for creating the 8-minute video?
DM: It took about four years to arrive at the final video. Keep in mind I basically started from scratch twice (first to change the 2001 lander to MER, and later to switch from the preliminary MER design to a model based on the final flight hardware). I was also finishing my undergraduate studies at Cornell during this time. If I had to make the video all over again, I estimate it would take about six months.
AM: From the Delta II launch vehicle to the planet topography and rover design, what did you find most challenging to create in such realistic ways?
DM: The rover was certainly a challenge due to its incredible geometric complexity. It was also quite difficult to generate convincing images of Mars from low altitude, since most of the available Mars data is either too large-scale or too small-scale for rendering purposes. The Viking maps and MOLA topography [Mars Orbital Laser Altimeter] don't have enough detail for close-up renderings, and MOC images [Mars Orbital Camera] are too narrow. For the MER animation, I ended up combining low-resolution Viking and MOLA data with hand-painted textures derived from MOC images.
|Dangling precariously between a supersonic parachute and the detached heatshield
Overall I think the weakest part of the animation is the Mars surface terrain. It doesn't quite capture the intricate details of the Martian rocks and soil. One day I hope to improve my terrain model so that I can render images that look just like panoramas from Pathfinder or MER.
AM: There was a relatively late decision to add horizontal rocket thrusters in case of a landing with significant martian wind. That addition proved important to the first lander particularly, since otherwise Spirit would have had a very hard airbag impact. Did that come too late to include in the final animation?
DM: Yes, the TIRS rockets were added a little too late to be included in the video. However, I did get a chance to animate the TIRS rockets (and what can happen if they were absent) for the NOVA documentary "Mars Dead or Alive."
(The entire hour-long documentary can be viewed on-line . I created about six minutes of original animation for it, in addition to the official NASA MER animation)
AM: Can you describe the rendering lab you maintain? It is mainly a Linux cluster you've constructed correct? Is that rendering with Blender or another animation tool with your custom code additions?
DM: I rendered the majority of the 3D elements in Lightwave running on Linux systems. I also rendered a few elements with Pixar's RenderMan renderer. RenderMan has better sampling and shading features, but it does not have a modeling/animation interface like Lightwave, so I wrote some software to convert Lightwave models and scenes to RenderMan. I also wrote a render controller which distributes tasks among my "render farm", which consists of 6-8 PCs.
AM: Is the bottleneck in doing such realistic animations at 24 frames per second still the processing power or was your research the hardest part?
DM: Until the last year or two, computer power was a significant bottleneck. Today computers have reached a speed where I can't generate animation quickly enough to keep them busy. Setting up keyframe animation, lighting, and surface textures are the most time-consuming tasks.
Rendering time for the MER animation varied between 2 minutes and 35 minutes per frame at [High Definition] HDTV resolution, with most Mars surface shots coming in at about 20 minutes per frame. I believe I will be able to reduce rendering time even further with more advanced techniques (on top of the automatic reduction that comes with faster computers).
|A low-resolution frame of Dan Maas' high quality video, showing Mars rover protected by descent-bracing airbag pyramid. Dust was kicked up onto the rover bags, making them 'instant' rocks in low resolution images that came back from the Spirit landing platform.
Credit: D. Maas/NASA/JPL/Cornell
AM: Many of your animation sequences are starting to work their way into other venues, like PBS Nova and BBC. The Superbowl had a few rover shots, and of course there have been many cuts shown that highlight a particular portion of the mission. What is the most surprising or unusual place or contact you have gotten since the landing or when the film first began circulating?
DM: The Superbowl broadcast was definitely a surprise (a clip of the rover aired as part of a "Choose to Vote" public service message). I heard a still image of the rover was also used by Saturday Night Live in their "Weekend Update" segment.
One of my favorite recent projects was creating three two-page spreads for TIME Magazine. TIME did a great job printing these; they looked spectacular.
It's amazing to think that at least 100 million people have probably seen my work in various places...
AM: Was the original thrust for the video from Cornell's Athena team, NASA, or did it just evolve in a way that once people starting viewing portions that the project grew in scope?
DM: The video started as part of Cornell's Athena public outreach program. Once people saw the animation, it was clearly going to play an important part in explaining the mission to the public. Last year we extended its original five-minute length to over nine minutes. The new material includes more bounces after landing, and an illustration of the rover's deployment over several Martian days.
I have mostly finished my collaboration with Cornell but I continue to work on graphics with Dr. Eric DeJong's team at JPL.
(Incidentally, I just finished a video for the NASA/JPL/UMD Deep Impact mission. It includes about 8 minutes of animation, although it's done in a more traditional documentary style than the MER video)
AM: The only unphysical part of the film was adding sound effects in the vacuum of space. That seems similar to the way the Star Trek series used to provide sounds for acceleration and warp drive. You have noted elsewhere that this was an add-on, but how did that artistic choice get made and what were the important reasons for that as sort of 'hyper-realism'--actually to feel one is riding the ship and feeling the vibration?
DM: Steve Squyres and I agreed that the video would have a lot less dramatic impact without the thunder of rocket engines, pyro firings, and fiery re-entry. The main vision for the launch and landing is to make the audience feel as if they are really there alongside the spacecraft.
Steve and I also agreed that there would be no spoken narration. I think it's obvious now that narration would have been a distraction. Plus, the video is often shown by speakers or at press conferences where someone wants to talk the audience through it.
AM: While watching the Mars coverage from static pictures, are there parts of the mission that particularly intrigue your eye, having spent so much time with the whole profile in front of you long before launch and landing?
|Spirit's first rock targets, in field of near driving targets
DM: It was mind-blowing to see the first images after each rover had driven off its lander. It looked almost exactly like the video! I'm very proud that I was able to capture those moments in animation, without ever having seen any of the flight hardware in person.
The part of the mission that fascinated me most was the terminal descent - from parachute to airbag inflation, descent rocket firing, and landing. The speed at which all this happens is amazing. In fact I recently saw the actual trajectory of Spirit's descent - it fell about twice as fast as I had shown in the animation! I would like to congratulate the JPL engineers for making this all work in real life. It's a tremendous accomplishment.
|Click for larger image.
Credit: NASA/JPL/ MSSS
AM: Is the animated site the one at Gusev crater as it was imagined by Dr. Squyres beforehand, or is that landscape a composite of many landscapes?
DM: The landscape in the video is actually based on Melas Chasma, part of Vallis Marinaris. At the time I created the video, this was one of the intended landing sites for MER. It was later ruled out due to high winds. We didn't have time to go back and re-create the terrain in my video for Gusev crater. But through pure luck it resembles Spirit's landing site quite a bit. The distant mountains in my video were intended to represent the walls of Vallis Marinaris, but they serve as a decent stand-in for the hills near Spirit's landing site.
AM: Future plans for other productions?
DM: I am about to start work on two more Mars Rover-related projects (confidential for now, but you'll know them when you see them). I also just released some of my custom software - a high-quality star field renderer - as a product other animators can use (see Starpro). I hope to market more of my software in the future.
Related Web Pages
Martian Chronicles: Steve Squyres' Mission Journals
James Cameron's Mars Design Reference
James Cameron III: Space, the Reality Show
James Cameron IV: The ET Challenge
Mars Reference Design Details
Pancam: Surveying the Scene - Martian Style
Interview with Nathalie Cabrol - Pasadena, Spirit Mission Sol 4