Rendering (computer graphics)

Rendering is the process of generating a <a href="/facts/Physically-based_rendering/bRK5alKl">photorealistic</a> or <a href="/facts/Non-photorealistic_rendering/r8qIQogo">non-photorealistic</a> image from input data such as <a href="/facts/3D_model/6V3Ry9AJ">3D models</a>. The word "rendering" (in one of its senses) originally meant the task performed by an artist when depicting a real or imaginary thing (the finished artwork is also called a "<a href="/facts/Architectural_rendering/lqtXU2fa">rendering</a>"). Today, to "render" commonly means to generate an image or video from a precise description (often created by an artist) using a <a href="/facts/Computer_program/e38jH9N9">computer program</a>.
A <a href="/facts/Application_software/YQuj7Kog">software application</a> or <a href="/facts/Component-based_software_engineering/eW5wvSHC">component</a> that performs rendering is called a rendering <a href="/facts/Software_engine/QhIAMMBg">engine</a>, render engine, rendering system, graphics engine, or simply a renderer.
A distinction is made between <a href="/facts/Real-time_computer_graphics/jrILnb0K">real-time rendering</a>, in which images are generated and displayed immediately (ideally fast enough to give the impression of motion or animation), and offline rendering (sometimes called <a href="/facts/Pre-rendering/YtB5k4Jh">pre-rendering</a>) in which images, or film or video <a href="/facts/Film_frame/27Uqo8WN">frames</a>, are generated for later viewing. Offline rendering can use a slower and higher-quality renderer. Interactive applications such as games must primarily use real-time rendering, although they may incorporate pre-rendered content.
Rendering can produce images of scenes or objects defined using coordinates in <a href="/facts/Three-dimensional_space/KAqKWUbS">3D space</a>, seen from a particular <a href="/facts/3D_projection/FATfGH2W">viewpoint</a>. Such <a href="/facts/3D_rendering/6SqukntK">3D rendering</a> uses knowledge and ideas from <a href="/facts/Optics/p0vq4S1T">optics</a>, the study of <a href="/facts/Visual_perception/g7Tfaq2l">visual perception</a>, <a href="/facts/Mathematics/pxTouaz4">mathematics</a>, and <a href="/facts/Software_engineering/KX6cE9kz">software engineering</a>, and it has applications such as <a href="/facts/Video_game/vmTdNASJ">video games</a>, <a href="/facts/Simulation/Q4QJV1oI">simulators</a>, <a href="/facts/Visual_effects/AdoEkAWU">visual effects</a> for films and television, <a href="/facts/Computer-aided_design/5gSXrmmN">design visualization</a>, and <a href="/facts/Medical_imaging/pL6JyJEp">medical diagnosis</a>. Realistic 3D rendering requires finding approximate solutions to the <a href="/facts/Rendering_equation/jQHVyQ18">rendering equation</a>, which describes how light propagates in an environment.
Real-time rendering uses high-performance <a href="/facts/Rasterization/QXfz5t7E">rasterization</a> algorithms that process a list of shapes and determine which <a href="/facts/Pixel/UzwBvXBV">pixels</a> are covered by each shape. When more realism is required (e.g. for <a href="/facts/Architectural_rendering/lqtXU2fa">architectural visualization</a> or <a href="/facts/Visual_effects/AdoEkAWU">visual effects</a>) slower pixel-by-pixel algorithms such as <a href="/facts/Ray_tracing_(graphics)/n6qpap2q">ray tracing</a> are used instead. (Ray tracing can also be used selectively during rasterized rendering to improve the realism of lighting and reflections.) A type of ray tracing called <a href="/facts/Path_tracing/fxhaM84b">path tracing</a> is currently the most common technique for photorealistic rendering. Path tracing is also popular for generating high-quality non-photorealistic images, such as frames for 3D animated films. Both rasterization and ray tracing can be sped up ("accelerated") by specially designed microprocessors called <a href="/facts/GPU/PTK1RQVp">GPUs</a>.
Rasterization algorithms are also used to render images containing only 2D shapes such as <a href="/facts/Polygon/yAq7RjPz">polygons</a> and <a href="/facts/Font_rasterization/FCUyDI2s">text</a>. Applications of this type of rendering include <a href="/facts/Digital_illustration/oy6tA2Gh">digital illustration</a>, <a href="/facts/Graphic_design/CJu4SYuG">graphic design</a>, 2D <a href="/facts/Animation/093f9nUg">animation</a>, <a href="/facts/Desktop_publishing/gUPtzSnH">desktop publishing</a> and the display of <a href="/facts/User_interface/e9sPEWVD">user interfaces</a>.
Historically, rendering was called image synthesis: xxi  but today this term is likely to mean <a href="/facts/Artificial_intelligence_art/d591uR6T">AI image generation</a>. The term "neural rendering" is sometimes used when a <a href="/facts/Neural_network_(machine_learning)/6V1jMlkx">neural network</a> is the primary means of generating an image but some degree of control over the output image is provided. Neural networks can also assist rendering without replacing traditional algorithms, e.g. by removing noise from path traced images.

Rendering (computer graphics) open-in-new

Rendering (computer graphics)