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Cel-shaded
Cel shading or toon shading is a type of non-photorealistic rendering designed to make 3-D computer graphics appear to be flat by using less shading color instead of a shade gradient or tints and shades. A cel shader is often used to mimic the style of a comic book or cartoon and/or give the render a characteristic paper-like texture. There are similar techniques that can make an image look like a sketch, an oil painting or an ink painting. The name comes from ''cels'' (short for celluloid), clear sheets of acetate which were painted on for use in traditional 2D animation. Basic process The cel-shading process starts with a typical 3D model. Where cel-shading differs from conventional rendering is in its non-photorealistic illumination model. Conventional smooth lighting values are calculated for each pixel and then quantized to a small number of discrete shades to create the characteristic "flat look", where the shadows and highlights appear as blocks of color ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celshading Teapot Large
Cel shading or toon shading is a type of non-photorealistic rendering designed to make 3-D computer graphics appear to be flat by using less shading color instead of a Color gradient, shade gradient or tints and shades. A cel shader is often used to mimic the style of a comic book or cartoon and/or give the render a characteristic paper-like texture. There are similar techniques that can make an image look like a Sketch (drawing), sketch, an oil painting or an ink painting. The name comes from cel, ''cels'' (short for celluloid), clear sheets of acetate which were painted on for use in Traditional animation, traditional 2D animation. Basic process The cel-shading process starts with a typical 3D computer graphics#Modeling, 3D model. Where cel-shading differs from conventional rendering is in its non-photorealistic illumination model. Conventional smooth lighting values are calculated for each pixel and then Color quantization, quantized to a small number of discrete shades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-photorealistic Rendering
Non-photorealistic rendering (NPR) is an area of computer graphics that focuses on enabling a wide variety of expressive styles for digital art, in contrast to traditional computer graphics, which focuses on photorealism. NPR is inspired by other artistic modes such as painting, drawing, technical illustration, and animated cartoons. NPR has appeared in movies and video games in the form of cel-shaded animation (also known as " toon" shading) as well as in scientific visualization, architectural illustration and experimental animation. History and criticism of the term The term ''non-photorealistic rendering'' is believed to have been coined by the SIGGRAPH 1990 papers committee, who held a session entitled "Non Photo Realistic Rendering". The term has received some criticism: * The term "photorealism" has different meanings for graphics researchers (see "photorealistic rendering") and artists. For artists—who are the target consumers of NPR techniques—it refers to a schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traditional Animation
Traditional animation (or classical animation, cel animation, or hand-drawn animation) is an animation technique in which each frame is drawn by hand. The technique was the dominant form of animation in cinema until computer animation. Process Writing and storyboarding Animation production usually begins after a story is converted into an animation film script, from which a storyboard is derived. A storyboard has an appearance somewhat similar to comic book panels, and is a shot by shot breakdown of the staging, acting and any camera moves that will be present in the film. The images allow the animation team to plan the flow of the plot and the composition of the imagery. Storyboard artists will have regular meetings with the director and may redraw or "re-board" a sequence many times before it meets final approval. Voice recording Before animation begins, a preliminary soundtrack or scratch track is recorded so that the animation may be more precisely synchronized to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Quantization
In computer graphics, color quantization or color image quantization is quantization applied to color spaces; it is a process that reduces the number of distinct colors used in an image, usually with the intention that the new image should be as visually similar as possible to the original image. Computer algorithms to perform color quantization on bitmaps have been studied since the 1970s. Color quantization is critical for displaying images with many colors on devices that can only display a limited number of colors, usually due to memory limitations, and enables efficient compression of certain types of images. The name "color quantization" is primarily used in computer graphics research literature; in applications, terms such as ''optimized palette generation'', ''optimal palette generation'', or ''decreasing color depth'' are used. Some of these are misleading, as the palettes generated by standard algorithms are not necessarily the best possible. Algorithms Most standard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multitexturing
Texture mapping is a method for mapping a texture on a computer-generated graphic. Texture here can be high frequency detail, surface texture, or color. History The original technique was pioneered by Edwin Catmull in 1974. Texture mapping originally referred to diffuse mapping, a method that simply mapped pixels from a texture to a 3D surface ("wrapping" the image around the object). In recent decades, the advent of multi-pass rendering, multitexturing, mipmaps, and more complex mappings such as height mapping, bump mapping, normal mapping, displacement mapping, reflection mapping, specular mapping, occlusion mapping, and many other variations on the technique (controlled by a materials system) have made it possible to simulate near-photorealism in real time by vastly reducing the number of polygons and lighting calculations needed to construct a realistic and functional 3D scene. Texture maps A is an image applied (mapped) to the surface of a shape or polygon. This m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utah Teapot
The Utah teapot, or the Newell teapot, is a 3D test model that has become a standard reference object and an in-joke within the computer graphics community. It is a mathematical model of an ordinary Melitta-brand teapot that appears solid with a nearly rotationally symmetrical body. Using a teapot model is considered the 3D equivalent of a "Hello, World!" program, a way to create an easy 3D scene with a somewhat complex model acting as the basic geometry for a scene with a light setup. Some programming libraries, such as the OpenGL Utility Toolkit, even have functions dedicated to drawing teapots. The teapot model was created in 1975 by early computer graphics researcher Martin Newell, a member of the pioneering graphics program at the University of Utah. It was one of the first to be modeled using bézier curves rather than precisely measured. History For his work, Newell needed a simple mathematical model of a familiar object. His wife, Sandra Newell, suggested mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z-buffering
A depth buffer, also known as a z-buffer, is a type of data buffer used in computer graphics to represent depth information of objects in 3D space from a particular perspective. Depth buffers are an aid to rendering a scene to ensure that the correct polygons properly occlude other polygons. Z-buffering was first described in 1974 by Wolfgang Straßer in his PhD thesis on fast algorithms for rendering occluded objects. A similar solution to determining overlapping polygons is the painter's algorithm, which is capable of handling non-opaque scene elements, though at the cost of efficiency and incorrect results. In a 3D-rendering pipeline, when an object is projected on the screen, the depth (z-value) of a generated fragment in the projected screen image is compared to the value already stored in the buffer (depth test), and replaces it if the new value is closer. It works in tandem with the rasterizer, which computes the colored values. The fragment output by the rasterizer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compositing
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most, though not all, compositing is achieved through digital image manipulation. Pre- digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use. Basic procedure All compositing involves the replacement of selected parts of an image with other material, usually, but not always, from another image. In the digital method of compositing, software commands designate a narrowly defined color as the part of an image to be replaced. Then the software (e.g. Natron) replaces every pixel within the designated color range with a pixel from another image, aligned to appear as part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertex Shader
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. Traditional shaders calculate rendering effects on graphics hardware with a high degree of flexibility. Most shaders are coded for (and run on) a graphics processing unit (GPU), though this is not a strict requirement. ''Shading languages'' are used to program the GPU's rendering pipeline, which has mostly superseded the fixed-function pipeline of the past that only allowed for common geometry transforming and pixel-shading functions; with shaders, customized effects can be used. The position and color ( hue, saturation, brightness, and contrast) of all pixels, vertices, and/or textures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertex Normal
In the geometry of computer graphics, a vertex normal at a vertex of a polyhedron is a directional vector associated with a vertex, intended as a replacement to the true geometric normal of the surface. Commonly, it is computed as the normalized average of the surface normals of the faces that contain that vertex. The average can be weighted for example by the area of the face or it can be unweighted. Vertex normals can also be computed for polygonal approximations to surfaces such as NURBS, or specified explicitly for artistic purposes. Vertex normals are used in Gouraud shading, Phong shading and other lighting models. Using vertex normals, much smoother shading than flat shading can be achieved; however, without some modifications, it cannot produce a sharp edge.Max Wagner, Generating Vertex Normals, https://web.archive.org/web/20130531101356/http://www.emeyex.com/site/tuts/VertexNormals.pdf References See also * Specular highlight * Per-pixel lighting In computer graphics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Frame Model
A wire-frame model, also wireframe model, is a visual representation of a three-dimensional (3D) physical object used in 3D computer graphics. It is 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. The object is projected into screen space and rendered by drawing lines at the location of each edge. The term "wire frame" comes from designers using metal wire to represent the three-dimensional shape of solid objects. 3D wire frame computer models allow for the construction and manipulation of solids and solid surfaces. 3D solid modeling efficiently draws higher quality representations of solids than conventional line drawing. Using a wire-frame model allows for the visualization of the underlying design structure of a 3D model. Traditional two-dimensional views and drawings/renderings can be created by the appropriate rotation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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