00:00.
00:06July 16, 1969, Apollo 11 blasted off from the Kennedy Space Center, carrying three astronauts
00:13on its perilous journey to the moon.
00:18Five days later, as the world watched with bated breath, astronauts Neil Armstrong and
00:23Buzz Aldrin became the first men to walk on the moon.
00:27But not everyone is convinced that this historic journey actually happened.
00:32Over the past 40 years, numerous theories have called into question the photographic evidence
00:37that has captivated the world.
00:42Then you hear about the fact that the landing was actually done in a television studio.
00:48And it was just a big black background with fake stars and stuff, just the flag being
00:52planted on the moon facing one way and the shadow of the man being the other way.
00:56I've heard that maybe the terrain that was seen on the video wasn't accurate, the walking
01:01wasn't accurate.
01:02There are no stars in some of the photographs and that there should be because there was
01:05no atmosphere and that the stars would shine so brightly.
01:08Those photographs can be demonstrated not to have been taken on the lunar surface.
01:13Now, if they were not taken on the lunar surface, there's only one other place they could have
01:17been taken and that's on Earth.
01:19On the surface, some of these claims seem reasonable, but do the scientific facts lend
01:24credence to these conspiracy theorists?
01:27So with our new technology in Maxwell, we have the ability to do something that's never
01:32been done before, which is global illumination in real time.
01:36What that means is I can actually simulate the bouncing of light off of multiple surfaces and
01:42lighting other objects.
01:43With that technology, we looked for what's the opportunity to show this off.
01:47And there's this very famous photograph of Buzz Aldrin as he was descending the ladder
01:52of the lunar module when they landed on the moon.
01:55We're modeling basically a real-time version of the Apollo 11 landing site in Unreal Engine
02:004.
02:00There's been a lot of speculation over the years about the lighting of that and whether,
02:03you know, the conspiracy theories of whether it's real.
02:06So we thought it would be cool to try to simulate the lighting of the landing site from
02:09an accurate point of view.
02:10We wanted to take on the challenge of showing, no, the single light source of the sun was
02:15actually able to light Buzz Aldrin even though he's in the shadows.
02:19The task was a huge undertaking and no detail was too small to overlook.
02:25It's actually reasonably difficult to get a physically accurate version of the moon because
02:29it has a lot of different properties than the Earth.
02:31The environment of the moon and the surfaces of the moon have their own peculiarities.
02:35For example, the moon has no atmosphere, so when you see the sun in the sky, you won't
02:40see a blue sky around it because there's no air in order to scatter that illumination into
02:46the blue colors that you normally see.
02:48To make sure that this is actually accurate, we did a lot of research on the different properties
02:51of the lunar soil, the spacesuit material, the material on the lander, looked at a lot
02:55of photos, the lunar landing area, satellite imagery of that.
02:58We actually had to model the landing site, an astronaut that was realistic to the Apollo
03:0211 spacesuits, model a land that matched the materials and the different colored regions
03:06on it and the shape of the lander legs and ladder and all that kind of thing.
03:09This all plays into how the image is created.
03:12After the painstaking process of getting every detail modeled in 3D, the team then had to
03:18create a physically accurate lunar lighting model.
03:21We have a bunch of different modes that you can adjust in the demo, sort of as a progression
03:25through the technology.
03:25And the first mode is basically showing it how it would be if there was no indirect light
03:29or no bounce light at all, so basically no global illumination.
03:32And that mode kind of simulates what it would look like just by default in most game engines.
03:37And that's the source of where a lot of the conspiracy theories come from, because when
03:40you look at that scene, Buzz Aldrin is completely in shadow because he's on the shadow side of
03:43the lamp.
03:44The way that we normally think about light is that it comes from a light source, it hits
03:48a surface, and then it reflects toward a camera.
03:50But actually, light's more complicated than that, because it doesn't just bounce straight
03:56to a camera.
03:56It also bounces and hits other parts of the scene.
03:59These inter-reflections make up a lot of the illumination content.
04:04The next step is basically adding additional point lights to simulate light bounced off the
04:09surfaces.
04:10And that just has to be placed by a human.
04:12And so if we enable that mode, you can see that it doesn't look very realistic at all.
04:15The next mode uses Maxwell's new rendering operations to render a more accurate view that actually
04:20does take into kind of specular reflections, bounce light off the ground.
04:23But even after the light was modeled using NVIDIA's voxel-based global illumination, the
04:29image still did not look right.
04:32Part of the challenge was we've got to get the surface reflection of the moon dust.
04:36We've got to get the reflection off of the lunar module.
04:38We got all of that in place and properly modeled, we thought, but the image still didn't look
04:43quite right.
04:43There was some additional light source that was just missing.
04:46Turns out we found a clip of videotape that was shot from the other side of the ladder.
04:52And as he's coming down the ladder from the opposite side, there is a huge glowing bright
04:57white light.
04:58And as we analyzed that video a little more, we realized it's Neil Armstrong himself.
05:02The bright white space suit that he was wearing reflected all that sunlight off of him and
05:09back onto Buzz Aldrin.
05:10So, essentially, Neil Armstrong himself was a light source in that scene.
05:15It makes sense when you look at, you know, the albedo value, which is the amount of light
05:18that's reflected into your eye, basically, from a surface.
05:21For the lunar soil, it's around, like, 12 percent.
05:23But the suits, because they're like a Teflon-coated material, they're around 80 to 90 percent.
05:28And so they're very reflective.
05:30It's almost like a mirror, except you can't see something in the reflection.
05:33It just reflects the light.
05:34Once we pulled that information in and actually modeled a second astronaut and the light coming
05:39off of him, the bounced light was correct.
05:41And Buzz Aldrin looked lit properly, as it did in that very famous photo taken in 1969.
05:48Another apparent anomaly in the photographic record is the lack of stars in the black sky.
05:54And some say they know why this obvious omission was made.
05:59Astronomers could have easily discerned that the star positions were not those that would
06:07have appeared in a photograph taken from the moon.
06:11So it's another case where they could not fake it, so they simply ignored it.
06:17The thing to remember is that when they're on the moon, the sun's up there in the sky,
06:22and it's effectively daytime for them.
06:24Now, if you took a camera and set it up in your own backyard, and set the camera settings
06:29so that it could get a good picture of everything that's in your backyard, and then kept those
06:34same settings, waited until the middle of the night, and tried to take a picture of the
06:38stars, you'd find out that you couldn't see anything.
06:41When you looked up at the sky, could you actually see the stars and the solar corona in spite of
06:46the glare?
06:47We were never able to see stars from the lunar surface or on the daylight side of the moon
06:53in by eye without looking through the optics.
06:56There actually is a star field in the sky, and we have an adjustable exposure on our camera,
07:01so if we crank up that exposure to see the stars, you can see the bright light of the moon's
07:08surface starts to glow and glow and get blown out, and they take over the entire scene.
07:14Global illumination techniques have been used by CG artists for over a decade, but has only
07:19recently become possible to have this physically based lighting in real time graphics.
07:25For the longest time, global illumination has been used in film and offline rendering to
07:31get the nice subtle look of lighting bouncing off of multiple surfaces.
07:36Unfortunately, it's just been too hard to do in real time.
07:39Now with Maxwell, however, we have enough horsepower to do global illumination in real time, so
07:45we can get that same kind of subtle lighting effect in games and all these real time applications
07:51because of the power of Maxwell.
07:53Maxwell makes this possible because in order to do the global illumination, we have to produce
07:56a voxelized version of the scene, and Maxwell is actually very efficient at doing multi-planar
08:01rendering, which is required to do this.
08:02It also can push a whole lot of polygons because computing different levels of detail of the
08:07voxelized data requires multiple paths over the scene, and so being able to atomically access
08:12memory much more efficiently, that allows you to compute this thing much faster than it
08:15was feasible before.
08:16When you compare the photo with the final rendering, they're actually strikingly similar, which
08:20I think lends credence to the fact that it's not a conspiracy.
08:22So the lunar landing demo is a very nice recreation, not just of the 3D geometry of everything that
08:30was in the scene at this landing site, but a lot of attention to detail as to how the materials
08:35would have reflected illumination, and where the light was coming from, and simulating that light
08:41hitting these materials.
08:42And that combination of attention to detail is why this thing can be regarded as a pretty
08:48good pass at what it would have really looked like up there on the moon.
08:51It's tough to prove a negative, right?
08:54Can I prove that they didn't shoot this thing on some Hollywood soundstage?
08:59Nope.
09:00I can't prove that.
09:01But what I can prove is that the lighting environment on the moon can indeed be modeled and run in
09:09real
09:10time on Maxwell, such that we can see that with that single light source of the sun and the
09:15bouncing of the light off the surface of the moon, we can see Buzz Aldrin while he's in shadow.
09:20So now in 2014, yes, I could go around and in real time, I could make a game of walking
09:26around on the moon, and it would look as real as it did in any of the photos that you
09:31saw from
09:33on the moon land.
09:34I could do that in 2014 technology.
09:36In 1969 technology?
09:38No way.
09:40We choose to go to the moon in this decade and do the other things.
09:44Not because they are easy, but because they are hard.
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