| 3D computer graphics |
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| Basics |
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3D modeling / 3D scanning |
| Primary Uses |
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3D models / Computer-aided design |
| Related concepts |
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CGI / Animation / 3D display |
In 3D computer graphics, 3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object (either inanimate or living) via specialized software. 3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data that is stored in the computer A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance (i 3D rendering is the 3D computer graphics process of automatically converting 3D Wire frame models into 2D images with 3D photorealistic effects on a computer 3D printing is a category of Rapid prototyping technology A three dimensional object is created by layering and connecting successive cross sections of material 3D computer graphics software refers to programs used to create 3D Computer-generated imagery. In 3D computer graphics, 3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object The term graphic design can refer to a number of artistic and professional disciplines which focus on visual communication and presentation A video game is a Game that involves interaction with a User interface to generate visual feedback on a video device. Visual effects (commonly shortened to Visual F/X or VFX) are the various processes by which imagery is created and/or manipulated outside the context of a Live See also Visualization and Information graphics Visualization is any technique for creating Images Diagrams or Virtual engineering is defined as integrating Geometric models and related engineering tools such as analysis and Simulation, optimization, and Decision Virtual reality ( VR) is a technology which allows a user to interact with a Computer-simulated environment be it a real or imagined one Computer animation Computer-generated imagery (also known as CGI) is the application of the field of Computer graphics or more specifically 3D computer graphics The bouncing ball animation (below consists of these 6 frames A 3D display is any Display device capable of conveying three-dimensional images to the viewer Texture mapping is a method for adding detail surface texture or colour to a computer-generated graphic or 3D model. Computer-generated imagery Computer animation is the art of creating moving images with the use of Computers It is a subfield of Computer graphics Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating the movement onto a digital model Skeletal animation, sometimes referred to as rigging is a technique in Computer animation, particularly in the animation of Vertebrates, in which a character is represented Crowd simulation is the process of simulating the movement of a large number of objects or characters now often appearing in 3D computer graphics for Film. Global illumination is a general name for a group of Algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes Volume rendering is a technique used to display a 2D projection of a 3D discretely sampled Data set. 3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data that is stored in the computer Mathematics is the body of Knowledge and Academic discipline that studies such concepts as Quantity, Structure, Space and Three-dimensional space is a geometric model of the physical Universe in which we live 3D computer graphics software refers to programs used to create 3D Computer-generated imagery. The product is called a 3D model. It can be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena. 3D rendering is the 3D computer graphics process of automatically converting 3D Wire frame models into 2D images with 3D photorealistic effects on a computer A computer is a Machine that manipulates data according to a list of instructions. Simulation is the imitation of some real thing state of affairs or process The model can also be physically created using 3D Printing devices. 3D printing is a category of Rapid prototyping technology A three dimensional object is created by layering and connecting successive cross sections of material
Models may be created automatically or manually. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. Plastic arts are those Visual arts that involve the use of Materials that can be moulded or modulated in some way often in three dimensions
Contents |
Models
3D models, the product of modeling procedures, are often created with special software applications called 3D modelers. Application software is a subclass of Computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform 3D computer graphics software refers to programs used to create 3D Computer-generated imagery. Being a collection of data (points and other information), 3D models can be created by hand, algorithmically (procedural modeling), or scanned. In Geometry, Topology and related branches of mathematics a spatial point describes a specific point within a given space that consists of neither Volume In Mathematics, Computing, Linguistics and related subjects an algorithm is a sequence of finite instructions often used for Calculation Procedural modeling is an umbrella term for a number of techniques in Computer graphics to create 3D models and textures from sets of rules A 3D scanner is a device that analyzes a real-world object or environment to collect data on its shape and possibly its appearance (i Though they most often exist virtually (on a computer or a file on disk), even a description of such a model on paper can be considered a 3D model. A computer is a Machine that manipulates data according to a list of instructions. A computer file is a block of Arbitrary Information, or resource for storing information which is available to a Computer program and is usually
3D models are widely used anywhere 3D graphics are used. The Fifth Element is a French 1997 Science fantasy, action, Comedy, Techno thriller film directed by 3D computer graphics software refers to programs used to create 3D Computer-generated imagery. LightWave 3D is a high end Computer graphics program developed by NewTek. 3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data that is stored in the computer Actually, their use predates the widespread use of 3D graphics on personal computers. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated Many computer games used pre-rendered images of 3D models as sprites before computers could render them in real-time. A personal computer Game (also known as a computer game or simply PC game) is a Video game played on a Personal computer, rather In Computer graphics, a sprite (also known by other names see Synonyms below is a two-dimensional/three-dimensional Image or Animation that
Today, 3D models are used in a wide variety of fields. The medical industry uses detailed models of organs. The movie industry uses them as characters and objects for animated and real-life motion pictures. The video game industry uses them as assets for computer and video games. The video game industry (formally referred to as Interactive entertainment) is the economic sector involved with the development, Marketing A video game is a Game that involves interaction with a User interface to generate visual feedback on a video device. The science sector uses them as highly detailed models of chemical compounds. The architecture industry uses them to demonstrate proposed buildings and landscapes. The engineering community uses them as designs of new devices, vehicles and structures as well as a host of other uses. In recent decades the earth science community has started to construct 3D geological models as a standard practice. Earth science (also known as geoscience, the geosciences or the Earth Sciences) is an all-embracing term for the Sciences related to the planet
A model is not technically a graphic until it is visually displayed. Due to 3D printing, 3D models are not confined to virtual space. 3D printing is a category of Rapid prototyping technology A three dimensional object is created by layering and connecting successive cross sections of material
Modeling processes
There are three popularly used means by which to represent a model:
- Polygonal modeling - Various vertices on an xyz grid are mapped out. In 3D computer graphics, polygonal modeling is an approach for modeling objects by representing or approximating their Surfaces using Polygons Polygonal In Mathematics, the Cartesian coordinate system (also called rectangular coordinate system) is used to determine each point uniquely in a plane The vertices are connected in a linear fashion to form a polygonal mesh. Used for example by Maya 3d.
- NURBS modeling - Curves are formed by defining control points and attaching a "weight" to each one. Non-uniform rational B-spline ( NURBS) is a mathematical model commonly used in Computer graphics for generating and representing curves and surfaces The curve follows (but does not necessarily interpolate) the points. Increasing the weight for a point will pull the curve closer to that point. NURBS are particularly suitable for organic modelling. Used for example by Rhino3d.
- Splines&Patches modeling - Curves which define the surface directly (Splines) used for example by Hash Animation:Master.
The modeling stage consists of shaping individual objects that are later used in the scene. There are a number of modeling techniques, including:
Modeling can be performed by means of a dedicated program (e. Constructive solid geometry (CSG is a technique used in Solid modeling. In Mathematics, a level set of a real -valued function f of n variables is a set of the form { ( x 1 A subdivision surface, in the field of 3D computer graphics, is a method of representing a smooth Surface via the specification of a coarser Piecewise linear g. , Maya, 3DS Max, Blender, Lightwave, Modo) or an application component (Shaper, Lofter in 3DS Max) or some scene description language (as in POV-Ray). Maya is a high-end 3D computer graphics and 3D modeling software package originally developed by Alias Systems Corporation, but now owned by 3ds Max (formerly 3D Studio MAX) is a modeling animation and rendering package developed by Autodesk Media and Entertainment. Blender is a free 3D graphics application It can be used for modeling, UV unwrapping texturing rigging, water simulations LightWave 3D is a high end Computer graphics program developed by NewTek. modo is an advanced polygon Subdivision surface, modeling sculpting 3D painting animation and rendering package developed by Luxology LLC. The Persistence of Vision Raytracer, or POV-Ray, is a Ray tracing program available for a variety of computer platforms In some cases, there is no strict distinction between these phases; in such cases modelling is just part of the scene creation process (this is the case, for example, with Caligari trueSpace and Realsoft 3D). trueSpace is free 3D computer graphics and animation software developed by Caligari Corporation.
Complex materials such as blowing sand, clouds, and liquid sprays are modeled with particle systems, and are a mass of 3D coordinates which have either points, polygons, texture splats, or sprites assign to them. The term particle system refers to a computer graphics technique to simulate certain fuzzy phenomena which are otherwise very hard to reproduce with conventional rendering techniques In Mathematics and its applications a coordinate system is a system for assigning an n - Tuple of Numbers or scalars to each point In Geometry, Topology and related branches of mathematics a spatial point describes a specific point within a given space that consists of neither Volume In Geometry a polygon (ˈpɒlɨɡɒn ˈpɒliɡɒn is traditionally a plane figure that is bounded by a closed path or circuit In Computer graphics, texture splatting is a method for combining different textures. In Computer graphics, a sprite (also known by other names see Synonyms below is a two-dimensional/three-dimensional Image or Animation that
Representation
Because the appearance of an object depends largely on the exterior of the object, boundary representations are common in computer graphics. The Utah teapot or Newell teapot is a 3D model which has become a standard reference object (and something of an In-joke) in the Computer graphics In Solid modeling and Computer-aided design, boundary representation &mdashoften abbreviated as B-rep or BREP &mdashis a method for representing Two dimensional surfaces are a good analogy for the objects used in graphics, though quite often these objects are non-manifold. In Mathematics, specifically in Topology, a surface is a Two-dimensional Manifold. A manifold is a mathematical space in which every point has a neighborhood which resembles Euclidean space, but in which the global structure may be Since surfaces are not finite, a discrete digital approximation is required: polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have been gaining some popularity in recent years. A polygon mesh or Unstructured grid is a collection of vertices edges and faces that defines the shape of a polyhedral object in 3D computer A subdivision surface, in the field of 3D computer graphics, is a method of representing a smooth Surface via the specification of a coarser Piecewise linear Volume rendering is a technique used to display a 2D projection of a 3D discretely sampled Data set. Level sets are a useful representation for deforming surfaces which undergo many topological changes such as fluids. In Mathematics, a level set of a real -valued function f of n variables is a set of the form { ( x 1 FLUID ( F ast L ight '''U'''ser '''I'''nterface D esigner is a graphical editor that is used to produce FLTK Source code
The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference into a polygon representation of a sphere, is called tessellation. "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe The circumference is the distance around a closed Curve. Circumference is a kind of Perimeter. A tessellation or tiling of the plane is a collection of Plane figures that fills the plane with no overlaps and no gaps This step is used in polygon-based rendering, where objects are broken down from abstract representations ("primitives") such as spheres, cones etc, to so-called meshes, which are nets of interconnected triangles. A cone is a three-dimensional Geometric shape that tapers smoothly from a flat round base to a point called the apex or vertex Meshes of triangles (instead of e. g. squares) are popular as they have proven to be easy to render using scanline rendering. Classification A square (regular Quadrilateral) is a special case of a Rectangle as it has four right angles and equal parallel sides Scanline rendering is an algorithm for visible surface determination, in 3D computer graphics,that works on a row-by-row basis rather than a Polygon -by-polygon Polygon representations are not used in all rendering techniques, and in these cases the tessellation step is not included in the transition from abstract representation to rendered scene.
Scene setup
Scene setup involves arranging virtual objects, lights, cameras and other entities on a scene which will later be used to produce a still image or an animation. A virtual camera is a series of Still cameras which are designed to behave as a motion camera or a simulated camera onto which a 3-D animation is projected when rendering
Lighting is an important aspect of scene setup. As is the case in real-world scene arrangement, lighting is a significant contributing factor to the resulting aesthetic and visual quality of the finished work. As such, it can be a difficult art to master. Lighting effects can contribute greatly to the mood and emotional response effected by a scene, a fact which is well-known to photographers and theatrical lighting technicians.
It is usually desirable to add color to a model's surface in a user controlled way prior to rendering. Most 3D modeling software allows the user to color the model's vertices, and that color is then interpolated across the model's surface during rendering. 3D computer graphics software refers to programs used to create 3D Computer-generated imagery. In Geometry, a vertex (plural "vertices" is a special kind of point. In the mathematical subfield of Numerical analysis, interpolation is a method of constructing new data points within the range of a Discrete set of This is often how models are colored by the modeling software while the model is being created. The most common method of adding color information to a 3D model is by applying a 2D texture image to the model's surface through a process called texture mapping. Texture mapping is a method for adding detail surface texture or colour to a computer-generated graphic or 3D model. Texture mapping is a method for adding detail surface texture or colour to a computer-generated graphic or 3D model. Texture images are no different than any other digital image, but during the texture mapping process, special pieces of information (called texture coordinates or UV coordinates) are added to the model that indicate which parts of the texture image map to which parts of the 3D model's surface. A digital image is a representation of a two-dimensional Image using ones and zeros (binary UV mapping is a 3D modeling process of making a 2D image representing a 3D model Textures allow 3D models to look significantly more detailed and realistic than they would otherwise.
Other effects, beyond texturing and lighting, can be done to 3D models to add to their realism. For example, the surface normals can be tweaked to affect how they are lit, certain surfaces can have bump mapping applied and any other number of 3D rendering tricks can be applied. ' Bump mapping' is a Computer graphics technique where at each Pixel, a perturbation to the Surface normal of the object being rendered is 3D computer graphics (in contrast to 2D computer graphics) are graphics that use a three-dimensional representation of geometric data that is stored in the computer
3D models are often animated for some uses. The bouncing ball animation (below consists of these 6 frames They can sometimes be animated from within the 3D modeler that created them or else exported to another program. If used for animation, this phase usually makes use of a technique called "keyframing", which facilitates creation of complicated movement in the scene. Computer-generated imagery Computer animation is the art of creating moving images with the use of Computers It is a subfield of Computer graphics A key frame in Animation and Filmmaking is a drawing which defines the starting and ending points of any smooth transition. With the aid of keyframing, one needs only to choose where an object stops or changes its direction of movement, rotation, or scale, between which states in every frame are interpolated. In the mathematical subfield of Numerical analysis, interpolation is a method of constructing new data points within the range of a Discrete set of These moments of change are known as keyframes. Often extra data is added to the model to make it easier to animate. For example, some 3D models of humans and animals have entire bone systems so they will look realistic when they move and can be manipulated via joints and bones, in a process known as skeletal animation. Skeletal animation, sometimes referred to as rigging is a technique in Computer animation, particularly in the animation of Vertebrates, in which a character is represented
Compared to 2D methods
3D Photorealistic effects are often achieved without wireframe modeling and are sometimes indistinguishable in the final form. Photorealism is the genre of painting based on making a painting of a Photograph. Some graphic art software includes filters that can be applied to 2D vector graphics or 2D raster graphics on transparent layers. Graphic art software is a subclass of Application software used for Graphic design, Multimedia development specialized image development, general
Advantages of wireframe 3D modeling over exclusively 2D methods include:
- Flexibility, ability to change angles or animate images with quicker rendering of the changes;
- Ease of rendering, automatic calculation and rendering photorealistic effects rather than mentally visualizing or estimating;
- Accurate photorealism, less chance of human error in misplacing, overdoing, or forgetting to include a visual effect.
Disadvantages compare to 2D photorealistic rendering may include a software learning curve and difficulty achieving certain hyperrealistic effects. In Semiotics and Postmodern philosophy, the term hyperreality characterizes the inability of Consciousness to distinguish Reality from Fantasy Some hyperrealistic effects may be achieved with special rendering filters included in the 3D modeling software. For the best of both worlds, some artists use a combination of 3D modeling followed by editing the 2D computer-rendered images from the 3D model.
3D model market
There is a large and thriving market for 3D models (as well as 3D-related content, such as textures, scripts, etc. ), either as individual models or large collections. Online marketplaces for 3D content allow individual artists to sell content that they have created. Often, the artists' goal is to get additional value out of assets they have previously created for projects. By doing so, artists can earn more money out of their old content, and companies can save money by buying pre-made models instead of paying an employee to create one from scratch. These marketplaces typically split the sale between themselves and the artist that created the asset, often in a roughly 50-50 split. In most cases, the artist retains ownership of the 3d model; the customer only buys the right to use and present the model.
Collections of hundreds to thousands of 3D models on CD, often royalty free, are for sale. These models include different types of people, animals, objects, plants, rocks, tools, furniture, buildings, landscapes, historical objects, cartoon characters, monsters, science fiction objects, medieval fantasy objects, etc. A person who buys such a CD can import these posable ready-made models into their computer animation program.
See also
- Computer facial animation
- Cloth modeling
- Digital geometry
- Geological modelling
- Image development
- SIGGRAPH
- Stanford Bunny
- Utah Teapot
- Voxel
References
External links
- A Critical History of Computer Graphics and Animation
- How Stuff Works - 3D Graphics
- History of Computer Graphics series of articles
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