3D computer graphics

Digitalized image of glass objects

Theather drawn by 3D graphic

3D computer graphics or computer graphics (in English 3D computer graphics) are graphics that use a three-dimensional representation of geometric data (often Cartesian) that are stored on the computer for the purpose of performing calculations and rendering 2D images, which can be stored for later viewing or displayed in real time. Furthermore, the term can refer to the process of creating such graphics, or to the field of study of techniques and technology related to 3D graphics.

A 3D graph differs from a two-dimensional one mainly by the way it has been generated. These types of graphics originate from a process of mathematical calculations on three-dimensional geometric entities produced on a computer, and whose purpose is to achieve a two-dimensional visual projection to be displayed on a screen or printed on paper.

In general, 3D graphics art is similar to sculpture or photography, while 2D graphics art is analogous to painting. In computer graphics programs this distinction is often blurred: some 2D applications use 3D techniques to achieve certain effects like lighting, while some primary 3D applications make use of 3D techniques.

History

William Fetter coined the term computer graphics in 1961 to describe his work at Boeing. One of the first exhibits of computer animation was Futureworld (1976), which included an animation of a human face and hand that had appeared previously in the 1972 experimental short film A Computer Animated Hand, created by Path University students Edwin Catmull and Fred Parke.

3D computer graphics software for home computers began to appear in the late 1970s. The first known example is 3D Art Graphics, a set of 3D graphic effects created by Kazumasa Mitazawa and released in June 1978 for the Apple II.

Creating 3D graphics

The process of creating 3D computer graphics can be divided into three basic stages:

Modeling

The modeling stage consists of shaping individual objects that will later be used in the created scene. There are several 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 one of them is a polygon; a pyramid consists of 4 triangles and a square base. However, a rounded shape is also represented by polygons, for example, a football is composed of 12 pentagons and 20 hexagons.
• Models defined by their mathematical curves (NURBS and Patch): There are currently other modeling systems where the user works with mathematically defined curved surfaces. One case is the circumference, which can be represented as a polygon of many sides, but also as a mathematical function between two variables: X and Y (the set of points of one plane that are equidistant from another). Likewise, the user works with a vector program (such as Illustrator or Freehand) to trace perfect curves in a non-polgonal 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, algorithms that control the incidence of light combine textures with materials of type: anthropy, Lambert, Blin, etc. are used.

• Lighting: Creation of punctual, directional lights in area or volume, with different color or properties. The lights kind omni generate light rays in all directions unlike the directionals in which light beams are directed to a single direction. In addition, some programmes deal with type lights Domo that illuminate the entire scene, as well as lights that take parameters of real lamp lab. In relation to the color, you can enable it according to the scene or composition you want to achieve and you can configure an environment with warm or cold colors, which are achieved by modifying the values of the RGB of each of the lights. However, there is another concept of enlightenment that is the Global (in English Global Ilumination), known as a set of algorithms that try to simulate or approach as a light, emitted by some source, rebounds on each surface of the scene illuminating spaces, which the direct light produced by the source would not reach to illuminate.

Animation

3D animation is a complex process, because it involves the prior realization 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 way 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 skeleton movement will automatically affect the corresponding parts of the model.
  • By deformers: they can be deformation boxes (Lattices) or any deformer that produces, for example, a sinusoidal deformation.
  • Using dynamics for simulations of clothing, hair, rigid object.

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

• Motion Design Technique: with this technique it is possible to have 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 fly what is obtained in 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 movement. Another version of this technique is the "go motion". In this variant is recorded the animation frame by frame.
• Pixilation: This technique has a great resemblance to the "stop motion". The only big difference is that pixilation does not work or represent objects, but people. The process is the same as with the previous technique, it is done by capturing images, either using a photo camera or a video camera. Then, these images move at a speed of 24 frames per second (fps), however, the speed can be different according to which format we want to export the video. This way, we create the movement.
• Hyperrealistic technique: this technique pretends that animated characters and objects are so real that it is hard to differentiate them from reality. The objective is that three-dimensional animation be as imperceptible as possible.
• Caricature technique: this technique tries to make much simpler reality to create fictional characters and objects that are fun for, for example, the smallest.
• Rotos Technique Copy: This technique was widely used by Disney, it is characterized by recording people making the move, then to heat the movement and thus generate a more realistic animation, this type of technique was in varia Disney animation productions one of them is Snow White and the 7 dwarfs.

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

First 3D animation (1972)

• The first 3D animation: In 1972, at the University of Utah, Edwin Catmull, the 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 filmed in Super 8 format, without sounds and, in black and white.

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

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

Rendering

By rendering realistic images are obtained

The final process of generating the 2D image or animation from the created scene is called rendering (from English render ). 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 images (frame).

The 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 such effects brings 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. by volumetric or caustic sampling (effect of light passing through refracting surfaces).

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

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

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

Computer applications

Despite there being many 3D modeling and animation packages, the most prominent are:

• Maya. It is the most popular modeling software, as it is used by a multitude of important visual effects studies in combination with RenderMan, Pixar's photorealist rénder engine.
• 3D Studio Max. He is the leader in the 3D development of the video game and is widely used at the amateur level.
• Blender. It is a program free of modeling, animation, lighting and rendering, with simulation of particles and physics of fluids, rigid and soft bodies in real time (necessary for your game engine), with possibility of editing and composition of images and video. You can import/export different 2D image formats (bmp, jpg...), 3D models and scenes (3ds, obj...) and also offer the possibility of programming scripts in Python.
• Lightwave 3D. It is used in many studios for visual effects and animation of cinema and television such as Digital Domain, Rhythm & Hues, Eden FX, Dreamworks, Flash Film Works, Pixel Magic, etc. It was developed by the Kansas NewTek Inc. company in 1989. The software consists of two parts: Modeler developed by Stuart Ferguson in 1986 and Layout developed by Allen Hastings in 1989. It later evolved into an advanced animation modelling package, VFX and render for various platforms: Amiga, PC Windows, Apple Macintosh, Silicon Graphics, Dec Alpha, Sun Microsystems and MIPS. It is currently available for Windows, Mac OS and Mac OS X.

In addition, there are other computer applications, but they are less common:

• Caligari trueSpace. Application in which all 3D graphics creation phases are performed within a single program. It provides features such as simulation of physical phenomena (wind, gravity, collisions between bodies).
• Cinema4d. Quick driving engine, radiosity calculation.
• formZ. It offers topological manipulation of geometries.
• 3D Rhinoceros. A powerful NURBS modeler.
• Softimage XSI. In 1987, Softimage Inc, a company located in Montreal, wrote SoftimageUD3D, which quickly became the most popular 3D program of that period. In 1994, Microsoft purchased Softimage Inc. and started rewriting SoftImageUD3D for Windows NT. The result was called SoftimageIVAXSI. In 1998 Microsoft sold Softimage to Avid. Subsequently, it was acquired by the company Autodesk, in 2015 it was launched its latest version.
• RealSoft3D. 3D modeler for Linux and Windows. Includes rénder.
• Universe (Electric Image). Modeling and animation package with one of the fastest driving engines that exist.
• POV-Ray. An advanced free Raytracing software. Use your own scene description language, with features such as macros, loops and conditional statements. It is completely free, although it was not released under GPL.
• Moray. Modeler for POV-Ray.
• Kerkythea. Free program that makes rendering realistic from the physical properties of light.

3D graphics API

3D graphics have become very popular, particularly in video games, to the point that specialized application programming interfaces (APIs) have been created to facilitate processes at all stages of the computer graphics generation. These interfaces have proven to be vital for developers of computer graphics hardware, as they provide a way for the programmer to abstractly access the hardware, taking advantage of such a video card.

The following interfaces for computer graphics are particularly popular:

• OpenGL
• Direct3D (subset of DirectX to produce interactive 3D graphics)
• RenderMan
• Metal
• Vulkan
• Mantle