Sintel: About Technological Art

    So 2011 has passed ... Ahead of the new year is the Year of the Dragon. Traditionally important and successful year, the year of battles and victories. The previous year passed in a typical setting of patent unrest, restructuring of the code bases of many products and the constant development of technologies. And yet an article about something else. The story will be about a girl named Sintel and the dragon from the short film Sintel , released by the Blender Foundation more than a year ago , but which became a huge incentive in the development of 3D-editor Blender for the whole of 2011. Of course, this article would have been good a year ago, but better late than never.

    The devil is hiding in the little things. In the framework of computer science, there is no such project that could manage to get away from the transition to a simplified model that does not correspond to the real world. An example is lighting, hair, fabrics, and many other things. Therefore, there will be many clickable images ( carefully, traffic! ). All models and scenes from the film are licensed under CC-BY 3.0 and are available as project svn archives .

    So let's get started. The plot begins with a battle scene in the land of the dragon. We meet the main character in the mountains when the Guardian attacks her. A tired and frozen girl manages to defeat him with his own spear.

    Back to the scene. The scene is represented by a set of polysets made by the method of sulphting. In its pure form, the snow surface is about a hundred megabytes. The fog is implemented as a cube with particles. When viewing old versions of this place, a surprise awaits us: there are three guards instead of one. Here they are: from left to right - Smith, Lao Tseu and Dark. In addition, another guard was planned inside the city. Four models with full rigging and facial emotions, but the final casting is only Lao Tseu. Back to the plot. Losing consciousness, she notices a yurt nearby and, taking a few steps from her last strength, falls backward ... A new scene. Syntel wakes up from the voice of the owner of the yurt - the shaman who saved and sheltered her. (image resolution 4096x1744).

    Here you can clearly see the effect of subsurface scattering on fingers that are practically luminous from the fire. Subsurface scattering in all scenes is an indispensable attribute of the skin and adds a noticeable share of realism.

    A little about the Syntel model. This is an extremely complex model with a large grid and huge textures, it is almost impossible to use it on Core2 + 4GB RAM, so I will describe the Sintel Lite model ( link to the model) It has about 800,000 polygons. At the time of the creation of the model, the modelers several times changed the method of creating hair. There is a traditional type of hair in the form of polygons with a hair texture. This method is actively used in the gaming industry, but even taking into account the possibility of animation using physics of soft bodies, the result is not very realistic. The result is much better when using special algorithms. However, at that time the hair simulator was in an unstable state. During the creation, the simulator was stabilized and as a result we observe hair from particles. The full version uses 25 thousand hair (for comparison: the average person has about 100 thousand). The trajectory of movement is determined for each hundred hairs, as a result of which strands of parallel hair are observed. Sintel’s hair physics isn’t used, on each scene, Syntel is combed by hand. And this is what the Sintel Lite model looks like before and after rendering:

    Narration Sintel returns us to her hometown, on the day when she met a dragon. Syntel is looking for food, holding in his hands the 250,000-polygonal durian fruit . Midges actively fly around. And only in ultra-high resolution can you notice that among the midges, another tiny head of Susanna flies . But Sintel's attention was drawn to the sound from the roof. What is worth paying attention to here? That's right, in the background, blurred by the effect of depth of field . Behind this effect is another low-poly model of Suzanne. The dragon’s wing is damaged, the fluid simulator calculates the movement of blood drops using the Navier-Stokes equation . Syntel helps to heal a wound.

    A new scene showing the departure of the night and the arrival of dawn. A new day in the city. The Scales little dragon runs / flies around the city, which allows you to see many small details. Firstly, they are residents. Brooke, the protagonist of Elephants Dream, immediately catches your eye . The friend came from 2005, so he is bald and even without eyebrows, due to which there are only 238,000 polygons. And 12 more such random characters. Who needs sunlight? The scene with the city is illuminated by 40 directional sources. The little dragon runs after the chicken, Sintel runs after the little dragon. At the U-turn, Syntel sprinkles a fruit basket with 10,000 polygons each. The city is bombarded with high-polygonal rubbish with even higher-polygon statues.

    It is not surprising that there were people who, against the backdrop of all random coincidences, saw the silhouette of a Big Buck Bunny in the sky .

    A new scene is the temple of the city of Ishtar on the mountain. Around her are not very randomly located at home. This is how it looks without birds and post-processing: Speaking of birds. Often in modern animation you can see a situation where several birds flap their wings with the same frequency and phase. This is due to the fact that the animation of movements is based on the cyclical repetition of an action, for example, a flap of wings. In Sintel, each bird is individual, and the flap of the wings is determined by the angle of flight, speed and random component. Here is the same temple with post-processing: From a technical point of view, I need to say about the Bloom effect.

    responsible for blurring light on the bright edges of the scene. The bright background “seeps” here into everything: walls, characters and creatures. Also, one cannot fail to notice that one object in the picture above is very similar to the Blender logo :).

    Model of a baby dragon at the time of animation (before applying sculpting) about 8 thousand polygons ( video model ). This is quite a bit, since it does not have hair, hair or particles. But after applying the 4 levels of sculpting, 8178 * 4 ^ 4 is obtained - more than 2 million micro-polygons. Draft view with GLSL shaders and a normal map instead of sculpting: Not an example is the polygons of an adult dragon that appears on the same stage ( model video ). Given the four-level sculpting (

    head sculpting, compressed to 6 minutes ), it turns out 5 million polygons. Below will be a render of a person with high resolution. And this is how an adult dragon looks like in a binding position: So, during another walk, Scales was captured by an adult dragon. Sintel leaves the city walls, makes his way through the jungle (render in 4k resolution): Through rains and storms. Complex heterogeneous fog, post-processing for applying rain. The Syntel model is equipped with a shape key that changes hair color, skin texture and the polygonal mesh of the face and body - see the video with the shape keys . It goes through the desert (the image is again 4k, but the blend file ). The effect of light from the sun (flare, not in the frame). At the time of making the film, Blender did not have Dynamic Paint functionality.

    , therefore, pre-drawn footprints in the sand appear with the help of masks. With the release of version 2.6, this effect can be obtained much easier. It goes through the snowy expanses. The vignetting effect is best seen here : darkening the image along the edges of the frame to attract the viewer's attention to the scene. Artificial photo-optical noise is also visible for 3D graphics. However, these two elements are used throughout the film. The story comes to the beginning, in which Sintel sits in the shaman’s hut and tells him the story. Sintel's face close-up: The reflection is the same face, but wounded and aged:

    After listening to the story, the shaman indicates Sintel, where is the purpose of her search. Finally she finds a cave. The cave, like a snow plain, is made using the sculpting method. At the entrance to the cave is a tree depicted on the handle of a keeper’s weapon. The same tree is the logo of the Sintel project. Hexagonal objects - the result of the Bokeh effect - a simulation of a lens diaphragm with six petals. Adult dragon eats cow carcass. In the low poly cow model, 1230 faces. After applying the five levels of sculpting in the model, about 1.2 million faces. And all this (as with most other objects) under three 4096x4096 textures: color, highlights and bump map. The baby dragon does not recognize Sintel, after which the adult dragon detects and attacks her. Particle and smoke simulator in all its glory:

    Sculpting on the dragon’s head in 4k resolution: During the fight, the dragon knocks Sintel down, but instead of killing her, he hesitates, and she takes advantage of the moment to hit the dragon with the death blow of a spear - and only then he sees a familiar scar and realizes that she Little Scales grew up and it was him who she just killed ... Looking at her reflection in a pool of blood, she realizes that not only the dragon has changed a lot - too much time has passed in finding a friend. The cave begins to crumble, and Sintel leaves it, leaving the body of the dragon. Outside, after some time having coped with the grief, she discards her armor, throws out her weapon and leaves. The small and now lonely cub of the dragon follows her ...

    Here ends the story described in the plot. However, these 15 minutes were a huge impetus to development and the motive for stabilizing branch 2.5 of the Blender editor. Already today you can download version 2.61 with a new engine for photorealistic rendering on GPU Cycles , a 3D tracking system , an ocean simulator and dynamic drawing .

    The plans of the Blender Foundation another short film, codenamed Mango. What will we see in it? 2012 will show!

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