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Morph target animation, per-vertex animation, shape interpolation, shape keys, or blend shapes [1] is a method of 3D computer animation used together with techniques such as skeletal animation. In a morph target animation, a "deformed" version of a mesh is stored as a series of vertex positions. In each key frame of an animation, the vertices are then interpolated between these stored positions.
The "morph target" is a deformed version of a shape. When applied to a human face, for example, the head is first modelled with a neutral expression and a "target deformation" is then created for each other expression. When the face is being animated, the animator can then smoothly morph (or "blend") between the base shape and one or several morph targets. [2] Typical examples of morph targets used in facial animation is a smiling mouth, a closed eye, and a raised eyebrow. Early 3D videogames, such as Quake [3] and Crash Bandicoot use per-vertex animation for all character animations.
When used for facial animation, these morph target are often referred to as "key poses". The interpolations between key poses when an animation is being rendered, are typically small and simple transformations of movement, rotation, and scale performed by the 3D software. [1]
Not all morph target animation has to be done by actually editing vertex positions. It is also possible to take vertex positions found in skeletal animation and then use those rendered as morph target animation.
An animation composed in one 3D application suite sometimes needs to be transferred to another, as for rendering. Because different 3D applications tend to implement bones and other special effects differently, the morph target technique is sometimes used to transfer animations between 3D applications to avoid export issues.
There are advantages to using morph target animation over skeletal animation. The artist has more control over the movements because they can define the individual positions of the vertices within a keyframe, rather than being constrained by skeletons. This can be useful for animating cloth, skin, and facial expressions because it can be difficult to conform those things to the bones that are required for skeletal animation.
However, there are also disadvantages. Vertex animation is usually a lot more labour-intensive than skeletal animation because every vertex position must be manually manipulated and, for this reason, the number of pre-made target morphs is typically limited. [1] Also, in methods of rendering where vertices move from position to position in-between frames, a distortion is created that does not happen when using skeletal animation. This is described by critics of the technique as looking "shaky"[ citation needed ]. On the other hand, this distortion may be part of the desired "look".
For large models, vertex animation requires significant memory and storage as the position of each modified vertex must be stored for each frame. In contrast, skeletal animation requires only the storage of bone transformations for each frame.
Computer animation is the process used for digitally generating moving images. The more general term computer-generated imagery (CGI) encompasses both still images and moving images, while computer animation only refers to moving images. Modern computer animation usually uses 3D computer graphics.
In 3D computer graphics, a wire-frame model is a visual representation of a three-dimensional (3D) physical object. It is based on a polygon mesh or a volumetric mesh, created by specifying each edge of the physical object where two mathematically continuous smooth surfaces meet, or by connecting an object's constituent vertices using (straight) lines or curves.
Gouraud shading, named after Henri Gouraud, is an interpolation method used in computer graphics to produce continuous shading of surfaces represented by polygon meshes. In practice, Gouraud shading is most often used to achieve continuous lighting on triangle meshes by computing the lighting at the corners of each triangle and linearly interpolating the resulting colours for each pixel covered by the triangle. Gouraud first published the technique in 1971. However, enhanced hardware support for superior shading models has yielded Gouraud shading largely obsolete in modern rendering.
Texture mapping is a method for mapping a texture on a computer-generated graphic. "Texture" in this context can be high frequency detail, surface texture, or color.
In 3D computer graphics, Phong shading, Phong interpolation, or normal-vector interpolation shading is an interpolation technique for surface shading invented by computer graphics pioneer Bui Tuong Phong. Phong shading interpolates surface normals across rasterized polygons and computes pixel colors based on the interpolated normals and a reflection model. Phong shading may also refer to the specific combination of Phong interpolation and the Phong reflection model.
Shading refers to the depiction of depth perception in 3D models or illustrations by varying the level of darkness. Shading tries to approximate local behavior of light on the object's surface and is not to be confused with techniques of adding shadows, such as shadow mapping or shadow volumes, which fall under global behavior of light.
Autodesk 3ds Max, formerly 3D Studio and 3D Studio Max, is a professional 3D computer graphics program for making 3D animations, models, games and images. It is developed and produced by Autodesk Media and Entertainment. It has modeling capabilities and a flexible plugin architecture and must be used on the Microsoft Windows platform. It is frequently used by video game developers, many TV commercial studios, and architectural visualization studios. It is also used for movie effects and movie pre-visualization. 3ds Max features shaders, dynamic simulation, particle systems, radiosity, normal map creation and rendering, global illumination, a customizable user interface, and its own scripting language.
Skeletal animation or rigging is a technique in computer animation in which a character is represented in two parts: a polygonal or parametric mesh representation of the surface of the object, and a hierarchical set of interconnected parts, a virtual armature used to animate the mesh. While this technique is often used to animate humans and other organic figures, it only serves to make the animation process more intuitive, and the same technique can be used to control the deformation of any object—such as a door, a spoon, a building, or a galaxy. When the animated object is more general than, for example, a humanoid character, the set of "bones" may not be hierarchical or interconnected, but simply represent a higher-level description of the motion of the part of mesh it is influencing.
In 3D computer graphics and solid modeling, a polygon mesh is a collection of vertices, edges and faces that defines the shape of a polyhedral object's surface. It simplifies rendering, as in a wire-frame model. The faces usually consist of triangles, quadrilaterals (quads), or other simple convex polygons (n-gons). A polygonal mesh may also be more generally composed of concave polygons, or even polygons with holes.
In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene—a process known as shading. Shaders have evolved to perform a variety of specialized functions in computer graphics special effects and video post-processing, as well as general-purpose computing on graphics processing units.
Anim8or is a freeware OpenGL-based 3D modeling and animation program by R. Steven Glanville, a software engineer at NVidia. Currently at stable version 1.01.1402, it is a compact program with several tools which would normally be expected in high-end, paid software. To date, every version released has been under 3 MB, despite the fact that it does not make full use of Windows' native interface, carrying some graphical elements of its own. Although few official tutorials have been posted by the author, many other users have posted their own on sites such as YouTube and the anim8or home page. While Anim8or was once comparable to other freeware 3D animation software such as Blender, it has seen less progression in recent years, with Blender now being more capable than before.
In 3D computer graphics, polygonal modeling is an approach for modeling objects by representing or approximating their surfaces using polygon meshes. Polygonal modeling is well suited to scanline rendering and is therefore the method of choice for real-time computer graphics. Alternate methods of representing 3D objects include NURBS surfaces, subdivision surfaces, and equation-based representations used in ray tracers.
Computer facial animation is primarily an area of computer graphics that encapsulates methods and techniques for generating and animating images or models of a character face. The character can be a human, a humanoid, an animal, a legendary creature or character, etc. Due to its subject and output type, it is also related to many other scientific and artistic fields from psychology to traditional animation. The importance of human faces in verbal and non-verbal communication and advances in computer graphics hardware and software have caused considerable scientific, technological, and artistic interests in computer facial animation.
Facial motion capture is the process of electronically converting the movements of a person's face into a digital database using cameras or laser scanners. This database may then be used to produce computer graphics (CG), computer animation for movies, games, or real-time avatars. Because the motion of CG characters is derived from the movements of real people, it results in a more realistic and nuanced computer character animation than if the animation were created manually.
Interactive skeleton-driven simulation is a scientific computer simulation technique used to approximate realistic physical deformations of dynamic bodies in real-time. It involves using elastic dynamics and mathematical optimizations to decide the body-shapes during motion and interaction with forces. It has various applications within realistic simulations for medicine, 3D computer animation and virtual reality.
3D computer graphics, sometimes called CGI, 3-D-CGI or three-dimensional computer graphics, are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering digital images, usually 2D images but sometimes 3D images. The resulting images may be stored for viewing later or displayed in real time.
Messiah is a 3D animation and rendering application developed by pmG Worldwide. It runs on the Win32 and Win64 platforms. It is marketed to run on Mac OS X and Linux via Wine. Messiah's fourth version, messiah:studio was released April 2009 and version 5.5b as messiah:animate was released November 2006. messiahStudio6 was released in April 2013. Messiah seems no longer maintained since 2013 (abandoned).
A vertex in computer graphics is a data structure that describes certain attributes, like the position of a point in 2D or 3D space, or multiple points on a surface.
Pose space deformation is a computer animation technique which is used to deform a mesh on skeleton-driven animation. Common use of this technique is to deform the shape of a mesh according to the angle of the joint bent. Although the name is commonly called Pose space deformation on many scholarly articles, 3D animation software rarely uses that name. On Autodesk Maya, it's implemented under the name Pose Deformer, and on Blender, it's implemented as Corrective Shape Keys. The first famous application of this technique was the cloth's movement on the first episode of the animated film The Animatrix. Industrial Light & Magic used a linear variant of this approach as one of the tools to animate the Hulk for The Avengers movie.
This is a glossary of terms relating to computer graphics.
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