CGI (computer-generated imagery) is the creation of still or animated visual content with imaging software. CGI is used to produce images for many purposes including visual art, advertising, anatomical modeling, architectural design, engineering, television shows, video game art and film special effects, as well as augmented reality (AR) and virtual reality (VR) applications. Show CGI is accomplished through various methods. The use of algorithms to generate fractals, for example, can produce complex visual patterns. Other methods include painting in a 2D pixel-based image editor and creating shapes to make images, as in a vector-based image editor. CGI can also be made from 3D graphics, either with ray tracing or by rasterized 3D graphics. Ray tracing simulates the way light acts upon surfaces on the level of photons, simulated by shader programming routines. Ray tracing can use complex methods to build shapes, such as non-uniform b-spline (NURBS), 3D primitive shapes (such as cubes, spheres, pyramids, etc.) or simple polygons (typically triangles or quadrangles – which are often called quads). It may take seconds or even minutes per frame to render in these complex methods but results can be photorealistic. Rasterized 3D, on the other hand, is specialized for real-time display of animated imagery as in computer and console video games. Due to the need to render multiple frames per second (ideally sixty or more), rasterized 3D uses simple polygons or quads to define shapes, with shaders more often consisting of textures that define the color, specularity, surface texture, glow and reflectivity. Complex visuals may be made by combining computer-generated images into film in layers, a technique known as compositing. This technique is often used in conjunction with actors on a green screen, to place them in a simulated background.
Vector graphics are computer images created using a sequence of commands or mathematical statements that place lines and shapes in a two-dimensional or three-dimensional space. In vector graphics, a graphic artist's work, or file, is created and saved as a sequence of vector statements. A vector graphic file describes a series of points to be connected. These files are sometimes called geometric files. Images created with tools such as Adobe Illustrator and Corel's CorelDRAW are usually vector image files. Simplified, vector graphics are like connect-the-dots drawings. What are vector graphics used for?Graphic artists, illustrators and designers use vector graphics for a variety of reasons, including the following:
Vector vs. rasterA raster graphics image maps bits directly to a display space, also called a bitmap. Raster graphics are made up of a fixed number of pixels, which makes them less scalable than vector graphics. At a certain point, when the raster image is enlarged enough, the edges become ragged, and it appears pixelated -- i.e., when the pixels become visible. Raster graphics cannot be scaled up without sacrificing image quality. Vector and raster images can look different. This is because vector graphics must have a separate shape for each color shade, while raster images can have every pixel be a different color, showing subtle color gradations and depth more clearly. At larger sizes, the edges of raster images become ragged and the images pixilate. Vector images are more scalable.There is also a one-to-one relationship between each pixel and the memory raster graphics occupies on a computer. Computers must store information for every pixel of a raster image, whereas vector images only store the series of points that need to be connected by lines, curves, etc. Consequently, vector files are usually smaller than raster files. Vector image files are easier to modify than raster image files for this reason. Vector and raster images can be converted into one another with the right software. Adobe Illustrator and Adobe Photoshop are examples of software that enable users to convert one image format to the other. Raster files are particularly good for portraying color depth, as each pixel can be a different color. And there are more pixels that can be unique colors than vectors that can be unique colors. This makes raster file formats good for editing digital photographs. Certain file types can include vector and raster elements -- PDF and SVG files are two examples. Advantages and disadvantages of vector graphicsIt is important to consider both the benefits and drawbacks of using vector files. Advantages
Disadvantages
Types of vector filesThere are several commonly used vector file types. They include the following:
Different file types are used for different tasks. For example, AI files are commonly used in print media and digital graphics. EPS files can be both raster and vector files. They typically contain a smaller design element that can be embedded in a larger design. This makes them suitable for sending logos, which are often incorporated into larger designs.
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