Left: Alby and Limbradur set out on a journey through space and time. All images: Softmachine. The challenge: The characters enter the three-dimensional spacetime grid Scientifically correct general theory of relativity in a fulldome environment machine has over 10 years of experience in making fulldome movies and immersive content. Dr. Peter Popp (director, producer, writer) has produced the fulldome movies Christoph Brandl Kaluoka’hina—The Enchanted Reef (2004), 3d Artist/Scientific Visualization Realm of Light (2008) and The Life of Trees Softmachine (2013), before tackling gravitation. With the [email protected] motto “emotional education,” Softmachine has focused on combining compelling story A century of general relativity Two friends on a magical journey lines with ambitious scientific content. In th that vein, The Secrets of Gravity (2016) care- The year 2015 marked the 100 anniversa- To that end, Softmachine’s new fulldome fully interweaves the journey of two friends ry of the release of Albert Einstein’s general movie The Secrets of Gravity: In the Footsteps of with the insights of the general theory of rela- theory of relativity (GTR). Ten years after Albert Einstein aims to introduce the GTR to a tivity. revolutionizing our comprehension of light broad audience. It presents Einstein’s findings in the special theory of relativity, Einstein did to children and adults in a fun and playful the same for the force of gravitation. While way, and in doing so alleviates fears about The transition effect overturning our understanding of gravity, he abstract physics. For the fusion of character action with also changed our view of the nature of space The 45-minute animated movie follows science documentary, we use a stylistic and time itself. Limbradur, a student of the school of magic, device, which we call the “transition effect.” Probed to its most subtle predictions who has become bored by all the sorcery. He’d By simply waving his magic wand, Limbra- and confirmed countless of times, the GTR rather be an astronaut when he’s grown up. dur has the power to transform the set of the remains a theory of unsurpassed accuracy One night he breaks into the Albert Einstein Albert Einstein museum into a form of “holo- and elegance. It reinforced Einstein’s status as museum, where he is caught by the resident deck.” With this virtual environment the a superstar of modern science and made him knowledge-robot Alby X3. Limbradur is as characters can easily transport the audience the epitome of a genius. Ironically, it is this intrigued by Alby’s acquaintance with Albert anywhere and anytime, no matter if it is far standing as a prodigy that leads to reserva- Einstein as the robot is fascinated by the boy’s away galaxies or abstract worlds of thought. tions about engagement with the GTR in the magical powers. So they make a deal, where These science sequences are accompanied greater public. People ask themselves, quite quirky Alby tells Limbradur all about gravity by the explanatory voiceover of know-it- understandably, how could they could ever and the secrets of space and time. all Alby, who is our guide through space and fathom a genius’ masterpiece? The Munich-based animation studio Soft- time. After a chapter about Isaac Newton and 50 Planetarian Vol 46 No 1 - March 2017 his discovery of gravity, the audience is intro- strate this fact, the Earth appears inside duced to the counter-intuitive phenomena of the grid. Its presence makes the lines the GRT. move towards the planet’s center of There are a number of challenges that come mass. This bend is what we feel as grav- with the task of bringing scientifically correct, itation. comprehensible—yet aesthetically pleasing— This three-dimensional representation content to the screen or the dome. Secrets was of gravity avoids numerous pitfalls asso- rendered in stereoscopic 3D, which adds to ciated with the two-dimensional pendant the technical demands, but also adds to the (more on that later). Most of all, the center The Earth’s mass is bending spacetime explanatory power of many of the images. of gravity is easily and correctly identifi- able as the Earth’s core. Making Space three-dimensional However, this presentation reaches its The characters enter a world that is far from limits when we want the planet to move reality. Through Limbradur’s magic they see through the lattice. The lines in front Einstein’s thought experiments come to life. of the Earth, in direction as if in flight, Step by step the museum, the earth, and even snap to its surface, whereas the lines on the stars and galaxies dissolve into nothing. the rear side flick back to their initial This black emptiness is crisscrossed by blue straight shape. We tested this animation, but deemed all the overlapping lines too glowing lines, extending in all directions. crowded for the viewer to discern what At last Limbradur and Alby find themselves The moon is circling inside Earth’s gravity well is happening. That’s why our Earth does standing in a semi-transparent lattice, where not drift into view, but magically mate- space is no longer just a notion of outer space, rializes inside the lattice. but one of dimension. Likewise, problematic is a scenario There is a well-established approach to with two planets inside the grid. Again, the GRT, where the dimensions of space are the progression of the lines gets increas- represented as a form of fabric. Usually this ingly chaotic and confusing. That’s the is a simple two-dimensional plane. Instead, reason why we have our thee-dimen- we show a three-dimensional grid, through sional space collapse into a flat plane for which we create a bigger spatial and emotion- the next shot. al impact. By placing the characters inside The Y-axis of our three-dimensional the 3D fabric, we invent a completely differ- Visible stars close to the sun during a total eclipse grid folds flat and leaves a smooth black ent immersive experience for the audience. plane with big blue lines intersected by This presentation comes with some caveats. If not for the characters, this world of blue smaller ones. lines leaves no point of reference for the eye We did tests to match the size of the to determine size. loops in the 3D and 2D grids and found To convey depth, one cannot simply add out that grid loops that are too small for more lines in the background, as they start to the three-dimensional are still too big for overlay each other and the image becomes the two dimensions. So in the 3D lattice confusing. That’s the reason why our lattice we use larger loops, whereas in the grid rapidly fades into the distance. we subdivide those bigger loops with smaller ones. For full effect of this sequence, Secrets Light from a distant star is bent by the sun’s gravity should be seen in stereoscopic 3D when possi- We also noticed, when the loops are ble. This is one of the cases where the some- too small or the camera is too far above and comprehensibility. We can, for example, times maligned 3D is not simply a gimmick, it respectively, a distracting moire effect sets but increases the perception of depth. in at the far edges of the grid. Then again, show two objects in movement and interac- the problem with straight lines in the dome tion with each other. In this case, the moon’s Bending space is much less pronounced on the flat surface. gravity is only a smaller dent inside the big For Einstein, space is not a rigid stage like It only becomes apparent when you tilt the funnel around the Earth. This fabric analogy in Newton’s theory. It is flexible. Being in a camera too far down, that the plane no longer is the common visualization of space in the bent space means that the shortest distance looks flat but convex. GRT. between two points is no longer a straight Below our two-dimensional grid, we see a line, but a curve. So we demonstrate this fact massive bulge forming. As the camera switch- Light going in curves by bending, waving, and deforming the lines es to the other side of the fabric, we realize The general theory of relativity’s first test- of our grid. it is again the planet Earth that’s causing the able consequence was the deflection of light But bending the lattice and seeing the bend depression. In this hollow the smaller moon by gravity. Einstein predicted that any suffi- are not the same thing when you produce circles around our planet, like a marble rolls cient mass, like a star or planet, would bend images for the dome. In fact, the curved screen inside a funnel. a beam of light passing close to it. From the of the dome makes straight lines look warped Here gravity is represented by the dent, perspective of the light, it is moving in a anyway. So a lot of testing went into bending pressed by the planet’s mass into the fabric straight line through space; it is space itself the lines far enough to be noticeable, but not of space. Showing space as three-dimensional that has a bent shape. too far as to affect the whole of the lattice. may be closer to the real world, but as already In Secrets we discuss Sir Arthur Edding- As Einstein showed, space is deformed by indicated, there are cases where the reduc- ton’s famous experiment from May 29, 1919.