{{short description|Type of 3D graphics accelerator}} {{use American English|date=October 2025}} [[File:Quake_Wars_Ray_Traced.ogv|thumb|''Quake Wars: Ray Traced'' was rendered using Intel's now-cancelled Xeon Phi PCI 3.0 board.]] '''Ray tracing hardware''' is application specific computer hardware designed for acceleration of ray tracing calculations, especially real-time raytracing of graphics for interactive applications.
==Ray tracing and rasterization== The problem of rendering 3D graphics can be conceptually presented as finding all intersections between a set of "primitives" (typically triangles or polygons) and a set of "rays" (typically one or more per pixel).<ref>[https://graphics.cg.uni-saarland.de/fileadmin/cguds/courses/old_courses/OpenRT/Siggraph0f5/Slusallek_Intro.ppt Introduction to real time raytracing]{{dead link|date=April 2018 |bot=InternetArchiveBot |fix-attempted=yes }} Course notes, Course 41, Philipp Slusallek, Peter Shirley, Bill Mark, Gordon Stoll, Ingo Wald, SIGGRAPH 2005, (powerpoint presentation), Slide 26 :<u>Comparison Rasterization vs. Ray Tracing (Definitions)</u> ''graphics.cg.uni-saarland.de''</ref>
Up to the 2010s, mass market graphic acceleration boards, called graphics processing units (GPUs), used rasterization algorithms. The ray tracing algorithm solves the rendering problem in a different way. In each step, it finds all intersections of a ray with a set of relevant primitives of the scene.
Both approaches have their own benefits and drawbacks. Rasterization can be performed using devices based on a stream computing model, one triangle at the time, and access to the complete scene is needed only once.{{Efn|For additional visualizations such as shadows, or reflections such as produced by a large flat body of water, an addition pass of the scene graph is required for each effect.}} The drawback of rasterization is that non-local effects, required for an accurate simulation of a scene, such as reflections and shadows are difficult; and refractions<ref>[http://www.cs.uiowa.edu/~cwyman/publications/projects/refractions.html Chris Wyman's Research: Interactive Refractions] {{webarchive|url=https://web.archive.org/web/20100702165822/http://www.cs.uiowa.edu/~cwyman/publications/projects/refractions.html |date=2010-07-02 }} Department of Computer Science at The University of Iowa, ''www.cs.uiowa.edu''</ref> nearly impossible to compute.
The ray tracing algorithm is inherently suitable for scaling by parallelization of individual ray renders.<ref>SaarCOR —A Hardware Architecture for Ray Tracing, Jörg Schmittler, Ingo Wald, Philipp Slusallek, Section 2, "Previous work"</ref> However, anything other than ray casting requires recursion of the ray tracing algorithm (and random access to the scene graph) to complete their analysis,<ref>SaarCOR —A Hardware Architecture for Ray Tracing, Jörg Schmittler, Ingo Wald, Philipp Slusallek, Section 3, "The Ray Tracing Algorithm"</ref> since reflected, refracted, and scattered rays require that various parts of the scene be re-accessed in a way not easily predicted. But it can easily compute various kinds of physically correct effects, providing much more realistic impression than rasterization.{{Efn|Rasterization methods are capable of generating realistic shadows (including shadows produced by partially transparent objects), and plane reflections easily (as of 2010), but do not easily implement reflections from non planar surfaces (excluding approximations using normal maps) or refractions.}}
The complexity of a well implemented ray tracing algorithm scales logarithmically;{{Efn|That is if X is the number of triangles, then the number of computations to complete the scene is proportional to log(X).}} this is due to objects (triangles and collections of triangles) being placed into BSP trees or similar structures, and only being analyzed if a ray intersects with the bounding volume of the binary space partition.<ref>[http://www.pcper.com/article.php?aid=506&type=expert&pid=3 Ray Tracing and Gaming - One Year Later] {{Webarchive|url=https://web.archive.org/web/20100917113836/http://www.pcper.com/article.php?aid=506&type=expert&pid=3 |date=2010-09-17 }} Daniel Pohl, 17/1/2008, via "PCperspective", ''www.pcper.com''</ref>{{Efn|The same methods can be used in rasterization; in a simplistic implementation, culling is limited to those BSP partitions that lie within the much larger viewing frustum (more advanced implementations including those that implement occlusion culling or predicated rendering scale better than linearly for complex (especially high occluded) scenes (note in common APIs: DirectX 10 ''D3D10_QUERY_OCCLUSION_PREDICATE'' [http://msdn.microsoft.com/en-us/library/ee415853(VS.85).aspx], in OpenGL 3.0 ''HP_occlusion_query'' ). With ray tracing the viewing frustum is replaced by the volume enclosed by a single ray (or ray bundle).}}
==Implementations== Various implementations of ray tracing hardware have been created, both experimental and commercial: * (1995) Advanced Rendering Technology (ART) founded in Cambridge, UK, based on a 1994 PhD thesis,<ref name="hpg2018_renderdrive">{{ cite conference | url=https://highperformancegraphics.org/wp-content/uploads/2018/Hot3D/HPG2018_RenderDrive.pdf | title=Cold Chips: ART's RenderDrive | conference=High-Performance Graphics | date=2018 | access-date=14 February 2026 }}</ref> to produce dedicated ray tracing silicon (initially the "AR250" chip, which accelerated ray-triangle intersection, bounding box traversal and shading), using a "RenderDrive" networked accelerator for off-line rendering.<ref>[http://www.art.co.uk ART company website] {{webarchive|url=https://web.archive.org/web/19961227053055/http://www.art.co.uk/ |date=1996-12-27 }} ''www.art.co.uk''</ref> Products were first shipped to customers in 1998.<ref>[http://www.art.co.uk/press/releases/980121_ar250.html ART press release] {{webarchive|url=https://web.archive.org/web/19980513074300/http://www.art.co.uk/press/releases/980121_ar250.html|date=1998-05-13}} ''ART Chips In To Accelerate Ray Traced Rendering''</ref> Software provided integration with Autodesk Maya and Max data formats, and utilized the Renderman scene description language for sending data to the processors (the .RIB or Renderman Interface Bytestream file format).<ref>[http://www.protograph.co.uk/artvps.html ALL ABOUT ARTVPS, PURE CARDS, RENDERDRIVES and RAYBOX] {{webarchive|url=https://web.archive.org/web/20090414075505/http://www.protograph.co.uk/artvps.html |date=2009-04-14 }} Mark Segasby (Protograph Ltd), ''www.protograph.co.uk''</ref> The original AR250 was described as "the first time ray-tracing has been reduced to a single-chip design", achieving ray-tracing performance at "15 times the speed of a 266-MHz Pentium II processor".<ref name="microprocessorreport19970915">{{ cite magazine | url=https://archive.org/details/microprocessor-report-yrs-1992-2000/111202/page/n1/mode/1up | title=New 3D Engines Redefine the Market | magazine=Microprocessor Report | date=15 September 1997 | access-date=14 February 2026 | pages=2 }}</ref> ART experienced difficulties at the turn of the century and was acquired by "ART VPS", co-founded by one of ART's founders.<ref name="hpg2018_renderdrive"/>{{rp|pages=43}} As of 2010, ART-VPS no longer produces ray tracing hardware but continues to produce rendering software.<ref name="art">{{ cite web | url=http://www.artvps.com/content/artvps | title=About ArtVPS | website=ArtVPS | date=2009 | access-date=7 June 2009 | archive-url=https://web.archive.org/web/20090607034740/http://www.artvps.com/content/artvps | archive-date=2009-06-07 }}</ref> * (1996) Researchers at Princeton university proposed using DSPs to build a hardware unit for ray tracing acceleration, named "TigerSHARK".<ref>[http://cscott.net/Publications/tigershark-thesis.pdf A Hardware Accelerated Ray-tracing Engine] Greg Humphreys, C. Scott Ananian (Independent Work), Department of Computer Science, Princeton University, 14/5/1996, ''cscott.net''.</ref> * (1999-2002) Implementations of volume rendering using ray tracing algorithms on custom hardware were carried out in 1999 by Hanspeter Pfister<ref>{{cite conference | conference = IEEE Hot Chips 11 | conference-url = https://hc11.hotchips.org/ | date = 1999-08-17 | location = Memorial Auditorium, Stanford University | url = https://old.hotchips.org/wp-content/uploads/hc_archives/hc11/3_Tue/hc99.s5.4.Pfister.pdf | access-date = 2025-12-27 | title = The vg500 Real-Time Ray-Casting ASIC | author = Hanspeter Pfister | publisher = Mitsubishi Electric Research Laboratories }}</ref> and researchers at Mitsubishi Electric Research Laboratories<ref>{{cite journal | url = http://people.csail.mit.edu/fredo/Book/Stuff/volumePro.pdf | title = The VolumePro Real-Time Ray-Casting System | author = Hanspeter Pfister | author2 = Jan Hardenbergh | author3 = Jim Knittely | author4 = Hugh Lauery | author5 = Larry Seiler | journal = ACM Transactions on Graphics | publisher = Mitsubishi Electric | date = April 1999 | citeseerx = 10.1.1.69.4091 | access-date = 2010-02-27 | archive-url = https://web.archive.org/web/20110616202224/http://people.csail.mit.edu/fredo/Book/Stuff/volumePro.pdf | archive-date = 2011-06-16 }}</ref> with the vg500 / VolumePro ASIC based system and in 2002 with FPGAs by researchers at the University of Tübingen with VIZARD II<ref>{{cite journal | url = http://www.doggetts.org/michael/Meissner-2002-VIZARDII.pdf | title = VIZARD II: An FPGA-based Interactive Volume Rendering System | journal = Graphics Hardware | year = 2002 | pages = 1–11 | first1 = Urs | last1 = Kanus | first2 = Gregor | last2 = Wetekam | first3 = Johannes | last3 = Hirche | first4 = Michael | last4 = Meißner | publisher = University of Tübingen / Philips Research Hamburg | location = Germany | access-date = 2025-12-27 | archive-url = https://web.archive.org/web/20110726002035/http://www.doggetts.org/michael/Meissner-2002-VIZARDII.pdf | archive-date = 2011-07-26 }}</ref> * (2002) The computer graphics laboratory at Saarland University headed by Dr.-Ing. Philipp Slusallek has produced prototype ray tracing hardware including the FPGA based fixed function data driven SaarCOR (Saarbrücken's Coherence Optimized Ray Tracer) chip<ref>{{cite thesis |last = Schmittler |first = Jörg |year = 2006 |title = SaarCOR - A Hardware-Architecture for Realtime Ray Tracing |url = https://graphics.cg.uni-saarland.de/publications/schmittler2006.html |degree = PhD |location = Saarbrücken, Germany |publisher = Saarland University |access-date = 2025-12-27}}</ref><ref>{{cite journal | url = http://graphics.cg.uni-saarland.de/fileadmin/cguds/papers/2002/gh02/Schmittler-AHardwareArchitectureForRayTracing.pdf | title = SaarCOR —A Hardware Architecture for Ray Tracing | journal = Graphics Hardware | year = 2002 | pages = 1–11 | first1 = Jörg | last1 = Schmittler | first2 = Ingo | last2 = Wald | first3 = Philipp | last3 = Slusallek | publisher = Computer Graphics Group, Saarland University | location = Germany | access-date = 2011-11-22 | archive-url = https://web.archive.org/web/20110814155510/http://graphics.cg.uni-saarland.de/fileadmin/cguds/papers/2002/gh02/Schmittler-AHardwareArchitectureForRayTracing.pdf | archive-date = 2011-08-14 }}</ref><ref>{{cite journal | title = Realtime Ray Tracing of Dynamic Scenes on an FPGA Chip | citeseerx=10.1.1.72.2947 | journal = Graphics Hardware | year = 2004 | author1 = Jörg Schmittler | author2 = Sven Woop | author3 = Daniel Wagner | author4 = Wolfgang J. Paul | author5 = Philipp Slusallek | publisher = Computer Science, Saarland University, Germany }}</ref> and a more advanced programmable (2005) processor, the Ray Processing Unit (RPU)<ref>{{cite journal | url = http://graphics.cg.uni-saarland.de/fileadmin/cguds/papers/2005/rpu_siggraph/RPU_SIGGRAPH05.pdf | title = RPU: A Programmable Ray Processing Unit for Realtime Ray Tracing | author = Sven Woop | author2 = Jorg Schmittler | author3 = Philipp Slusallek | journal = ACM Transactions on Graphics | volume = 24 | issue = 3 | pages = 434–444 | publisher = Saarland University | access-date = 2011-11-22 | archive-url = https://web.archive.org/web/20120415113958/http://graphics.cg.uni-saarland.de/fileadmin/cguds/papers/2005/rpu_siggraph/RPU_SIGGRAPH05.pdf | archive-date = 2012-04-15 }}</ref> *(2009–2010) Intel<ref>{{Cite web|title=Sean Maloney's IDF 2009 Larrabee graphics demo - YouTube|url=https://www.youtube.com/watch?v=G-FKBMct21g |archive-url=https://ghostarchive.org/varchive/youtube/20211221/G-FKBMct21g |archive-date=2021-12-21 |url-status=live|access-date=2021-01-06|website=www.youtube.com| date=22 September 2009 }}{{cbignore}}</ref> showcased their prototype "Larrabee" GPU and Knights Ferry MIC, both built around x86 general-purpose manycore processors, at the Intel Developer Forum in 2009 with a demonstration of real-time raytracing. * (2009) Caustic Graphics<ref>[http://www.caustic.com/ Caustic Graphics company website] ''www.caustic.com''</ref> produced a plug in card, the "CausticOne",<ref>{{Cite web |date=2009-04-20 |title=Caustic Graphics Ray Tracing Acceleration Technology Review - PC Perspective |url=https://pcper.com/2009/04/caustic-graphics-ray-tracing-acceleration-technology-review/3/ |access-date=2022-08-05 |website=pcper.com |language=en-US}}</ref> that accelerated global illumination and other ray based rendering processes when coupled to a PC CPU and GPU. The hardware is designed to organize scattered rays (typically produced by global illumination problems) into more coherent sets (lower spatial or angular spread) for further processing by an external processor.<ref>[http://www.drdobbs.com/hpc-high-performance-computing/218500694 Reinventing Ray Tracing] 15/7/2009, Jonathan Erickson interview with James McCombe of Caustic Graphics, ''www.drdobbs.com''</ref> * (2010-2011) Siliconarts<ref>[http://www.siliconarts.com Siliconarts company website] ''www.siliconarts.com''</ref> developed a dedicated real-time ray tracing hardware (2010). RayCore, which is the world's first real-time ray tracing semiconductor IP, was announced in 2011. * (2013) Imagination Technologies, after acquiring Caustic Graphics, produced the Caustic Professional's R2500 and R2100 plug in cards containing RT2 ray trace units (RTUs). Each RTU was capable of calculating up to 50 million incoherent rays per second.<ref>{{Cite web|title = The future of ray tracing, reviewed: Caustic's R2500 accelerator finally moves us towards real-time ray tracing {{!}} ExtremeTech|url = http://www.extremetech.com/extreme/161074-the-future-of-ray-tracing-reviewed-caustics-r2500-accelerator-finally-moves-us-towards-real-time-ray-tracing|date = 2013-08-01|website = ExtremeTech|access-date = 2015-10-05}}</ref> * (2018, January) Nvidia, partnering with Microsoft DirectX, announced the Nvidia RTX developer library,<ref>{{Cite news|url=https://developer.nvidia.com/rtx|title=NVIDIA RTX™ Technology|date=2018-03-06|work=NVIDIA Developer|access-date=2018-04-20|language=en}}</ref> which promised fast GPU software ray tracing solutions in the Volta-generation GPUs.<ref>{{Cite news|url=https://www.anandtech.com/show/12546/nvidia-unveils-rtx-technology-real-time-ray-tracing-acceleration-for-volta-gpus-and-later|archive-url=https://web.archive.org/web/20180319182838/https://www.anandtech.com/show/12546/nvidia-unveils-rtx-technology-real-time-ray-tracing-acceleration-for-volta-gpus-and-later|url-status=dead|archive-date=March 19, 2018|title=NVIDIA Announces RTX Technology: Real Time Ray Tracing Acceleration for Volta GPUs and Later|last=Oh|first=Nate|access-date=2018-04-20}}</ref> * (2018, September) Nvidia introduced their GeForce RTX and Quadro RTX GPUs, based on the Turing architecture, with hardware-accelerated ray tracing using a separate functional block, publicly called an "RT core". This unit is somewhat comparable to a texture unit in size, latency, and interface to the processor core. The unit features BVH traversal, compressed BVH node decompression, ray-AABB intersection testing, and ray-triangle intersection testing.<ref>{{cite web|url=https://developer.nvidia.com/blog/nvidia-turing-architecture-in-depth|title=NVIDIA Turing Architecture In-Depth|last1=Kilgariff|first1=Emmett|last2=Moreton|first2=Henry|last3=Stam|first3=Nick|last4=Bell|first4=Brandon|website=Nvidia Developer|date=2018-09-14|access-date=2022-11-13|archive-url=https://web.archive.org/web/20221113010753/https://developer.nvidia.com/blog/nvidia-turing-architecture-in-depth/|archive-date=2022-11-13|url-status=live}}</ref> The GeForce RTX 2080 and 2080 Ti became the first consumer-oriented brand of graphics card that can perform ray tracing in real time.<ref>{{cite web|url=https://venturebeat.com/games/nvidia-unveils-geforce-rtx-graphics-chips-for-real-time-ray-tracing-games|title=Nvidia unveils GeForce RTX graphics chips for real-time ray tracing games|last=Takahashi|first=Dean|work=VentureBeat|date=2018-08-20|access-date=2022-11-13|archive-url=https://web.archive.org/web/20221113013850/https://venturebeat.com/games/nvidia-unveils-geforce-rtx-graphics-chips-for-real-time-ray-tracing-games|archive-date=2022-11-13|url-status=live}}</ref> * (2020) AMD announced further information regarding the "refresh" of the RDNA micro-architecture. According to the company, the RDNA 2 micro-architecture supports real-time hardware accelerated ray tracing, consisting of BVH node decoding, ray-AABB intersection testing, and ray-triangle intersection testing.<ref>{{cite web|url=https://www.eurogamer.net/articles/digitalfoundry-2020-10-28-amd-unveils-three-radeon-6000-graphics-cards-with-ray-tracing-and-impressive-performance|title=AMD unveils three Radeon 6000 graphics cards with ray tracing and RTX-beating performance|last=Judd|first=Will|work=Eurogamer|date=October 28, 2020|access-date=October 28, 2020}}</ref><ref>{{cite web|url=https://www.anandtech.com/show/16077/amd-announces-ryzen-zen-3-and-radeon-rdna2-presentations-for-october-a-new-journey-begins|archive-url=https://web.archive.org/web/20200910074941/https://www.anandtech.com/show/16077/amd-announces-ryzen-zen-3-and-radeon-rdna2-presentations-for-october-a-new-journey-begins|url-status=dead|archive-date=September 10, 2020|title=AMD Announces Ryzen "Zen 3" and Radeon "RDNA2" Presentations for October: A New Journey Begins|website=anandtech.com|publisher=AnandTech|date=2020-09-09|access-date=2020-10-25}}</ref> * (2021) Imagination Technologies announced their IMG CXT GPU with hardware-accelerated ray tracing.<ref>{{Cite web |last=93digital |date=2021-11-04 |title=Imagination launches the most advanced ray tracing GPU |url=https://www.imaginationtech.com/news/imagination-launches-the-most-advanced-ray-tracing-gpu/ |access-date=2023-09-17 |website=Imagination |language=en-GB}}</ref><ref>{{Cite web |title=Ray Tracing |url=https://www.imaginationtech.com/products/ray-tracing/ |access-date=2023-09-17 |website=Imagination |language=en-GB}}</ref> * (2022, January) Samsung announced their Exynos 2200 AP SoC with hardware-accelerated ray tracing based on the AMD RDNA2 GPU architecture.<ref>{{Cite web |title=Samsung Introduces Game Changing Exynos 2200 Processor With Xclipse GPU Powered by AMD RDNA 2 Architecture |url=https://news.samsung.com/global/samsung-introduces-game-changing-exynos-2200-processor-with-xclipse-gpu-powered-by-amd-rdna-2-architecture |access-date=2023-09-17 |website=news.samsung.com |language=en}}</ref> * (2022, June) Arm announced their Immortalis-G715 with hardware-accelerated ray tracing.<ref>{{Cite web |date=2022-06-28 |title=Gaming Performance Unleashed with Arm's new GPUs - Announcements - Arm Community blogs - Arm Community |url=https://community.arm.com/arm-community-blogs/b/announcements/posts/gaming-performance-unleashed |access-date=2023-09-17 |website=community.arm.com |language=en}}</ref> * (2022, November) Qualcomm announced their Snapdragon 8 Gen 2 with hardware-accelerated ray tracing.<ref>{{Cite web |title=Snapdragon 8 Gen 2 Defines a New Standard for Premium Smartphones |url=https://www.qualcomm.com/news/releases/2022/11/snapdragon-8-gen-2-defines-a-new-standard-for-premium-smartphone |access-date=2023-09-17 |website=www.qualcomm.com |language=en}}</ref><ref>{{Cite web |title=New, Snapdragon 8 Gen 2: 8 extraordinary mobile experiences, unveiled |url=https://www.qualcomm.com/news/onq/2022/11/new-snapdragon-8-gen-2-8-extraordinary-mobile-experiences-unveiled |access-date=2023-09-17 |website=www.qualcomm.com |language=en}}</ref> * (2022, December) Intel released the Arc Alchemist GPU,<ref>{{Cite web |title=Intel officially launches Arc A380 desktop graphics card in China, costs 153 USD |url=https://videocardz.com/newz/intel-officially-launches-arc-a380-desktop-graphics-card-in-china-costs-153-usd |access-date=2022-12-13 |website=VideoCardz.com |language=en-US}}</ref><ref>{{Cite web |last=Tyson |first=Mark |date=2022-09-28 |title=Intel Arc A310 Graphics Card Quietly Goes Official |url=https://www.tomshardware.com/news/intel-arc-a310-quietly-goes-official |access-date=2022-12-13 |website=Tom's Hardware |language=en}}</ref><ref>{{Cite news |date=2022-10-12 |title=Intel Arc A770 and Arc A750 graphics cards now available to buy from $289 |language=en-US |work=XDA Developers |url=https://www.xda-developers.com/intel-arc-a770-and-arc-a750-graphics-cards-now-available-to-buy-from-289/ |access-date=2022-12-13}}</ref> featuring ray tracing acceleration cores which perform comparatively with RTX 3000 series mid-range GPU.<ref>{{Cite web |date=2022-10-08 |title=Does ray tracing work on the Intel Arc GPUs? |url=https://www.digitaltrends.com/computing/does-ray-tracing-work-on-intel-arc-gpus/ |access-date=2022-12-13 |website=Digital Trends |language=en}}</ref> * (2023) Apple announced their Apple A17 with hardware-accelerated ray tracing.<ref>{{Cite web |last=Bonshor |first=Ryan Smith, Gavin |title=The Apple 2023 Fall iPhone Event Live Blog (Starts at 10am PT/17:00 UTC) |url=https://www.anandtech.com/show/20051/the-apple-2023-fall-iphone-event-live-blog |archive-url=https://web.archive.org/web/20230912170341/https://www.anandtech.com/show/20051/the-apple-2023-fall-iphone-event-live-blog |url-status=dead |archive-date=September 12, 2023 |access-date=2023-09-17 |website=www.anandtech.com}}</ref> A month later Apple announced the M3 chip family for Mac computers with support for hardware-accelerated ray tracing.<ref>{{Cite web |title=Apple unveils M3, M3 Pro, and M3 Max, the most advanced chips for a personal computer |url=https://www.apple.com/newsroom/2023/10/apple-unveils-m3-m3-pro-and-m3-max-the-most-advanced-chips-for-a-personal-computer/ |access-date=2024-10-27 |website=Apple Newsroom |language=en-US}}</ref>
==Notes== {{Notelist}}
==References== {{Reflist|30em}}
==Further reading== * [http://www.flipcode.net/archives/State-of-the-Art%20in%20interactive%20ray%20tracing.pdf State of the Art in Interactive Ray Tracing] Ingo Wald and Philipp Slusallek, Computer Graphics Group, Saarland University, Review article to year 2001
{{Graphics Processing Unit}}
{{DEFAULTSORT:Ray Tracing Hardware}} Category:3D rendering Category:Graphics hardware Category:Ray tracing (graphics)