Editing Rendering (computer graphics) (section)

{{Short description|Process of generating an image from a model}}
{{Redirect-distinguish|Image synthesis|Text-to-image model}}
{{About||rendering of HTML|Browser engine}}
[[Image:Glasses 800 edit.png|thumb|An image rendered using [[POV-Ray]] 3.6]]
[[File:Architectural render 02 (Blender).jpg|thumb|An architectural visualization rendered in multiple styles using [[Blender (software)|Blender]]]]
<!-- Deleted image removed: [[Image:CNC Rotary Table edit.png|thumb|UCAM CNC Rotary Table rendered image created by using [[Solidworks]] 2012]] -->
'''Rendering''' is the process of generating a [[physically-based rendering|photorealistic]] or [[Non-photorealistic rendering|non-photorealistic]] image from input data such as  [[3D model]]s. 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 "[[architectural rendering|rendering]]"). Today, to "render" commonly means to generate an image or video from a precise description (often created by an artist) using a [[computer program]].<ref>{{cite encyclopedia |title=Oxford English Dictionary |entry=Rendering, N., Sense IV.9.a |date=March 2024 | doi=10.1093/OED/1142023199}}</ref><ref>{{cite encyclopedia |title=Oxford English Dictionary |entry=Render, V., Sense I.3.b |date=June 2024 | doi=10.1093/OED/1095944705}}</ref><ref>{{cite encyclopedia |title=Oxford English Dictionary |entry=Rendering, N., Sense III.5.a |date=March 2024 | doi=10.1093/OED/1143106586}}</ref><ref>{{cite encyclopedia |title=Oxford English Dictionary |entry=Render, V., Sense IV.22.a |date=June 2024 | doi=10.1093/OED/1039673413}}</ref>

A [[application software|software application]] or [[component-based software engineering|component]] that performs rendering is called a '''rendering [[software engine|engine]]''',<ref>{{cite web | url=https://arvisual.eu/dictionary/rendering-engine/#:~:text=Definition,with%20a%20given%203D%20software. | title=What is a Rendering Engine? &#124; Dictionary | access-date=2024-02-21 | archive-date=2024-02-21 | archive-url=https://web.archive.org/web/20240221024025/https://arvisual.eu/dictionary/rendering-engine/#:~:text=Definition,with%20a%20given%203D%20software. | url-status=live }}</ref> '''render engine''', '''[[:Category: Rendering systems|rendering system]]''', '''graphics engine''', or simply a '''renderer'''.

A distinction is made between [[Real-time computer graphics|real-time rendering]], in which images are generated and displayed immediately (ideally fast enough to give the impression of motion or animation), and offline rendering (sometimes called [[pre-rendering]]) in which images, or film or video [[Film frame|frames]], 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 [[Three-dimensional space|3D space]], seen from a particular [[3D projection|viewpoint]]. Such [[3D rendering]] uses knowledge and ideas from [[optics]], the study of [[visual perception]], [[mathematics]], and [[software engineering]], and it has applications such as [[video game]]s, [[simulation|simulators]], [[visual effects]] for films and television, [[Computer-aided design|design visualization]], and [[medical imaging|medical diagnosis]]. Realistic 3D rendering requires modeling the propagation of light in an environment, e.g. by applying the [[rendering equation]].

Real-time rendering uses high-performance ''[[rasterization]]'' algorithms that process a list of shapes and determine which [[pixel]]s are covered by each shape. When more realism is required (e.g. for [[architectural rendering|architectural visualization]] or [[visual effects]]) slower pixel-by-pixel algorithms such as ''[[Ray tracing (graphics)|ray tracing]]'' 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 ''[[path tracing]]'' 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 [[GPU]]s.

Rasterization algorithms are also used to render images containing only 2D shapes such as [[polygon]]s and [[Font rasterization|text]]. Applications of this type of rendering include [[digital illustration]], [[graphic design]], 2D [[animation]], [[desktop publishing]] and the display of [[user interface]]s.

Historically, rendering was called '''image synthesis'''{{r|Glassner95|p=xxi}} but today this term is likely to mean [[Artificial intelligence art|AI image generation]].<ref>{{Cite conference | last1=Rombach | first1=Robin | last2=Blattmann | first2=Andreas | last3=Lorenz | first3=Dominik | last4=Esser | last5=Ommer | first5=Björn | date=June 2022 | title=High-Resolution Image Synthesis with Latent Diffusion Models | conference=2022 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) | doi=10.1109/CVPR52688.2022.01042 | pages=10674–10685| arxiv=2112.10752 }}</ref> The term "neural rendering" is sometimes used when a [[Neural network (machine learning)|neural network]] is the primary means of generating an image but some degree of control over the output image is provided.<ref>{{cite journal |title=State of the Art on Neural Rendering |last1=Tewari |first1=A. |last2=Fried |first2=O. |last3=Thies |first3=J. |last4=Sitzmann |first4=V. |last5=Lombardi |first5=S. |last6=Sunkavalli |first6=K. |last7=Martin-Brualla |first7=R. |last8=Simon |first8=T. |last9=Saragih |first9=J. |last10=Nießner |first10=M. |last11=Pandey |first11=R. |last12=Fanello |first12=S. |last13=Wetzstein |first13=G. |last14=Zhu |first14=J.-Y. |last15=Theobalt |first15=C. |last16=Agrawala |first16=M. |last17=Shechtman |first17=E. |last18=Goldman |first18=D.B. |last19=Zollhöfer |first19=M. |journal=ACM Transactions on Graphics |volume=39 |issue=2 |date=May 2020 |pages=701–727 |doi=10.1111/cgf.14022 |arxiv=2004.03805 }}</ref> Neural networks can also assist rendering without replacing traditional algorithms, e.g. by removing noise from path traced images.