Scene composition

This stage tries to distribute the different elements (objects, lights, cameras...) in a scene that will be used to produce a static image or an animation. Below are the different aspects that are part of the composition of a scene:

• - Shadow: Definition of the shape of the shadows of objects. To do this, materials called shaders are used, algorithms that control the incidence of light by combining textures with materials such as: anisotropy, Lambert, Blin, etc.

• - Lighting: Creation of point lights, directional in area or volume, with different colors or properties. Omni type lights generate light rays in all directions, unlike directional lights in which the light rays are directed in a single direction. In addition, some programs deal with dome type lights that illuminate the entire scene, as well as lights that take laboratory parameters from real lamps. In relation to color, it can be enabled according to the scene or composition that you want to achieve and you can configure an environment with warm or cold colors, which are achieved by modifying the RGB values ​​of each of the lights. However, there is another lighting concept which is Global Illumination, known as a set of algorithms that try to simulate or approximate how a light, emitted by some source, bounces off each surface of the scene, illuminating spaces, which the direct light produced by the source would not be able to illuminate.

3D animation is a complex process, because it involves the prior completion of other processes such as the design and modeling of the object to be animated. It consists of the deformation or movement of objects in a 3D model over time. For there to be animation, this deformation or movement must vary in some aspect with respect to time: change of lights and shapes, movement of objects and cameras, etc.

Objects can be animated from:.

• - Basic transformations in the three axes (XYZ), rotation, scale and translation.

• - Modifications in forms:

• Through skeletons: objects can be assigned a skeleton, a central structure with the ability to affect the shape and movements of that object. This helps the animation process, in which the movement of the skeleton will automatically affect the corresponding parts of the model.

• Using deformers: they can be deformation boxes (lattices) or any deformer that produces, for example, a sinusoidal deformation.

• Through dynamics for simulations of clothing, hair, rigid objects.

On the other hand, these are the main 3D animation techniques that are used today:

• - Motion Design Technique: with this technique it is possible to provide real movement to a three-dimensional object. The process consists of capturing movements using sensors and markers that are placed on real people or objects. These sensors and markers convert what was obtained into the 3D models. This technique is used very often in the world of video games.

• - Stop Motion Technique: this technique allows us to animate static objects by incorporating images without any movement. Another version of this technique is "go motion." In this variant, the animation is recorded frame by frame.

• - Pixilation: this technique is very similar to "stop motion". The only big difference is that pixilation does not work or represent objects, but rather people. The process is the same as with the previous technique, it is carried out by capturing images, either using a photo or video camera. These images are then moved at a speed of 24 frames per second (fps), however, the speed may be different depending on the format we want to export the video in. In this way, we create movement.

• - Hyperrealistic Technique: this technique aims to make animated characters and objects so real that it is difficult to differentiate them from reality. The goal is for the three-dimensional animation to be as imperceptible as possible.

• - Caricature technique: this technique attempts to make reality much simpler to create fictional characters and objects that are fun for, for example, the little ones.

• - Broken copy technique: This technique was widely used by Disney, it is characterized by recording people making the movement, to then trace the movement and thus generate a more realistic animation, this type of technique was in several Disney animation productions, one of them is Snow White and the 7 Dwarfs.

Animation is very important within graphics, because in these animations we try to imitate reality itself. Some previous experiences in the field of 3D animation are:

• - The first 3D animation: In 1972, at the University of Utah, Edwin Catmull, current founder of Pixar, with the help of his colleagues Fred Parke and Robert Ingerbretsen created one of the first 3D digital animations in history. The film was shot in Super 8 format, without sounds and in black and white.

• - The first 3D movie: Toy Story, the first film with three-dimensional animation effects, generating more than $550 million in profits produced by Pixar. After Disney's acquisition of the company, Edwin Catmull became president of Walt Disney Studios.

Currently, the world of 3D animation has evolved with the fact that anyone has enough means to create their own basic animation.

Rendering

The process of representing a 3D scene in a 2D image is called rendering. That is, in this part everything that is polygon, shadows, reflections, lighting, etc. is processed. To give realistic images, this can be rendered as a single image or as a video made up of many frames.

Rendering software can simulate cinematic effects such as lens flare, depth of field, or motion blur. These elements are a product of the mechanical imperfections of physical photography, but the simulation of these effects adds an element of realism to the scene. Techniques have been developed with the purpose of simulating atmospheric or natural effects such as rain, smoke, fire, fog, etc. through volumetric sampling or caustics "Caustics (optics)") (effect of light passing through refracting surfaces).

The rendering process requires simulating a large number of complex physical processes. Over the years, the processing power of computers has increased, allowing for a higher level of realism in renderings. Many movie studios use render farms to generate images more quickly and efficiently.

One of the most well-known and used rendering engines is V-Ray for its ease of configuration and its good quality results.

There are different rendering methods for both GPU and CPU, apart from V-Ray there are others such as Arnold, Octane, Redshift, Corona, cycles, eevee.

Modeling

The modeling stage consists of shaping individual objects that will later be used in the created scene. There are various types of geometry to model with NURBS and polygonal modeling or subdivision surfaces (in English subdivision surfaces). In addition, there is another type called "image based modeling" or in English image based modeling (IBM), which consists of converting a photograph to 3D through the use of various techniques, for example, photogrammetry whose main promoter is Paul Debevec.

There are two types of modeling techniques that are the most representative within modeling:

• - Models represented by polygons: One of the systems used by the computer to represent any structure are polygons. A cube has 6 faces, therefore, each of them is a polygon; A pyramid "Pyramid (geometry)") is made up of 4 triangles and a square base. However, a rounded shape is also represented by polygons, for example, a soccer ball is made up of 12 pentagons and 20 hexagons.

• - Models defined by their mathematical curves (NURBS and Patch "Patch (computing)"): Currently there are other modeling systems where the user works with mathematically defined curved surfaces. One case is the circumference, which can be represented as a polygon with many sides, but also as a mathematical function between two variables: X and Y (the set of points on a plane that are equidistant from another). Likewise, the user works with a vector program (such as Illustrator or Freehand) to draw perfect curves in a non-polygonal modeler, and also has different types of tools (NURBS, Spline, Patch, Bezier, etc.) to create complex curved surfaces.

Scene composition

This stage tries to distribute the different elements (objects, lights, cameras...) in a scene that will be used to produce a static image or an animation. Below are the different aspects that are part of the composition of a scene:

• - Shadow: Definition of the shape of the shadows of objects. To do this, materials called shaders are used, algorithms that control the incidence of light by combining textures with materials such as: anisotropy, Lambert, Blin, etc.

• - Lighting: Creation of point lights, directional in area or volume, with different colors or properties. Omni type lights generate light rays in all directions, unlike directional lights in which the light rays are directed in a single direction. In addition, some programs deal with dome type lights that illuminate the entire scene, as well as lights that take laboratory parameters from real lamps. In relation to color, it can be enabled according to the scene or composition that you want to achieve and you can configure an environment with warm or cold colors, which are achieved by modifying the RGB values ​​of each of the lights. However, there is another lighting concept which is Global Illumination, known as a set of algorithms that try to simulate or approximate how a light, emitted by some source, bounces off each surface of the scene, illuminating spaces, which the direct light produced by the source would not be able to illuminate.

3D animation is a complex process, because it involves the prior completion of other processes such as the design and modeling of the object to be animated. It consists of the deformation or movement of objects in a 3D model over time. For there to be animation, this deformation or movement must vary in some aspect with respect to time: change of lights and shapes, movement of objects and cameras, etc.

Objects can be animated from:.

• - Basic transformations in the three axes (XYZ), rotation, scale and translation.

• - Modifications in forms:

• Through skeletons: objects can be assigned a skeleton, a central structure with the ability to affect the shape and movements of that object. This helps the animation process, in which the movement of the skeleton will automatically affect the corresponding parts of the model.

• Using deformers: they can be deformation boxes (lattices) or any deformer that produces, for example, a sinusoidal deformation.

• Through dynamics for simulations of clothing, hair, rigid objects.

On the other hand, these are the main 3D animation techniques that are used today:

• - Motion Design Technique: with this technique it is possible to provide real movement to a three-dimensional object. The process consists of capturing movements using sensors and markers that are placed on real people or objects. These sensors and markers convert what was obtained into the 3D models. This technique is used very often in the world of video games.

• - Stop Motion Technique: this technique allows us to animate static objects by incorporating images without any movement. Another version of this technique is "go motion." In this variant, the animation is recorded frame by frame.

• - Pixilation: this technique is very similar to "stop motion". The only big difference is that pixilation does not work or represent objects, but rather people. The process is the same as with the previous technique, it is carried out by capturing images, either using a photo or video camera. These images are then moved at a speed of 24 frames per second (fps), however, the speed may be different depending on the format we want to export the video in. In this way, we create movement.

• - Hyperrealistic Technique: this technique aims to make animated characters and objects so real that it is difficult to differentiate them from reality. The goal is for the three-dimensional animation to be as imperceptible as possible.

• - Caricature technique: this technique attempts to make reality much simpler to create fictional characters and objects that are fun for, for example, the little ones.

• - Broken copy technique: This technique was widely used by Disney, it is characterized by recording people making the movement, to then trace the movement and thus generate a more realistic animation, this type of technique was in several Disney animation productions, one of them is Snow White and the 7 Dwarfs.

Animation is very important within graphics, because in these animations we try to imitate reality itself. Some previous experiences in the field of 3D animation are:

• - The first 3D animation: In 1972, at the University of Utah, Edwin Catmull, current founder of Pixar, with the help of his colleagues Fred Parke and Robert Ingerbretsen created one of the first 3D digital animations in history. The film was shot in Super 8 format, without sounds and in black and white.

• - The first 3D movie: Toy Story, the first film with three-dimensional animation effects, generating more than $550 million in profits produced by Pixar. After Disney's acquisition of the company, Edwin Catmull became president of Walt Disney Studios.

Currently, the world of 3D animation has evolved with the fact that anyone has enough means to create their own basic animation.

Rendering

The process of representing a 3D scene in a 2D image is called rendering. That is, in this part everything that is polygon, shadows, reflections, lighting, etc. is processed. To give realistic images, this can be rendered as a single image or as a video made up of many frames.

Rendering software can simulate cinematic effects such as lens flare, depth of field, or motion blur. These elements are a product of the mechanical imperfections of physical photography, but the simulation of these effects adds an element of realism to the scene. Techniques have been developed with the purpose of simulating atmospheric or natural effects such as rain, smoke, fire, fog, etc. through volumetric sampling or caustics "Caustics (optics)") (effect of light passing through refracting surfaces).

The rendering process requires simulating a large number of complex physical processes. Over the years, the processing power of computers has increased, allowing for a higher level of realism in renderings. Many movie studios use render farms to generate images more quickly and efficiently.

One of the most well-known and used rendering engines is V-Ray for its ease of configuration and its good quality results.

There are different rendering methods for both GPU and CPU, apart from V-Ray there are others such as Arnold, Octane, Redshift, Corona, cycles, eevee.