Editing Crowd simulation (section)

{{Short description|Model of movement}}
{{3D computer graphics}}
'''Crowd simulation''' is the process of simulating the movement (or '''{{vanchor|dynamics|CROWD_DYNAMICS}}''') of a large number of entities or characters.<ref>{{cite book |doi=10.1007/978-3-319-08234-9_69-1 |chapter=Crowd Simulation |title=Encyclopedia of Computer Graphics and Games |pages=1–8 |year=2016 |last1=Thalmann |first1=Daniel |isbn=978-3-319-08234-9 }}</ref> It is commonly used to create [[Virtual cinematography|virtual scene]]s for visual media like films and [[video game]]s, and is also used in crisis training,<ref>{{cite conference |url=http://cc.ist.psu.edu/BRIMS/archives/2007/papers/07-BRIMS-025.pdf |archive-url=https://web.archive.org/web/20161221001136/http://cc.ist.psu.edu/BRIMS/archives/2007/papers/07-BRIMS-025.pdf |archive-date=2016-12-21 |first1=Jérôme |last1=Comptdaer |first2=Emmanuel |last2=Chiva |first3=Stéphane |last3=Delorme |first4=Henri |last4=Morlaye |first5=Jérôme |last5=Volpoët |title=Multi-scale behavioral models for urban crisis training simulation |pages=317 |conference=16th Conference on Behavior Representation in Modeling and Simulation 2007 |date=March 2007 }}</ref> architecture and urban planning,<ref>{{cite journal |doi=10.1162/pres.16.3.318 |title=Design and Evaluation of a Real-World Virtual Environment for Architecture and Urban Planning |journal=Presence: Teleoperators and Virtual Environments |volume=16 |issue=3 |pages=318–32 |year=2007 |last1=Drettakis |first1=George |last2=Roussou |first2=Maria |last3=Reche |first3=Alex |last4=Tsingos |first4=Nicolas |url=https://hal.inria.fr/inria-00607261/file/DRRT07.pdf }}</ref> and evacuation simulation.<ref>{{cite journal |doi=10.1016/S0360-1323(98)00057-2 |title=A review of the methodologies used in the computer simulation of evacuation from the built environment |journal=Building and Environment |volume=34 |issue=6 |pages=741–9 |year=1999 |last1=Gwynne |first1=S. |last2=Galea |first2=E.R. |last3=Owen |first3=M. |last4=Lawrence |first4=P.J. |last5=Filippidis |first5=L. |bibcode=1999BuEnv..34..741G }}</ref>

Crowd simulation may focus on aspects that target different applications. For realistic and fast [[rendering (computer graphics)|rendering]] of a crowd for visual media or [[virtual cinematography]], reduction of the complexity of the [[3D scene]] and [[image-based rendering]] are used,<ref>{{cite journal |doi=10.1111/1467-8659.00633 |title=Visualizing Crowds in Real-Time |journal=Computer Graphics Forum |volume=21 |issue=4 |pages=753–65 |year=2002 |last1=Tecchia |first1=Franco |last2=Loscos |first2=Celine |last3=Chrysanthou |first3=Yiorgos }}</ref> while variations (changes) in appearance help present a realistic population.<ref name="Thalmann et al 2009">{{cite book |doi=10.1109/CW.2009.23 |chapter=Challenges in Crowd Simulation |title=2009 International Conference on CyberWorlds |pages=1–12 |year=2009 |last1=Thalmann |first1=Daniel |last2=Grillon |first2=Helena |last3=Maim |first3=Jonathan |last4=Yersin |first4=Barbara |isbn=978-1-4244-4864-7 |url=https://infoscience.epfl.ch/record/159013/files/CW2009.pdf }}</ref><ref name="Maim et al 2009">{{cite journal |doi=10.1109/MCG.2009.129 |pmid=24806782 |title=Unique Character Instances for Crowds |journal=IEEE Computer Graphics and Applications |volume=29 |issue=6 |pages=82–90 |year=2009 |last1=Maim |first1=J. |last2=Yersin |first2=B. |last3=Thalmann |first3=D. }}</ref>

In games and applications intended to replicate real-life [[human]] crowd movement, like in evacuation simulations, simulated agents may need to navigate towards a goal, avoid collisions, and exhibit other human-like behavior. Many crowd steering algorithms have been developed to lead simulated crowds to their goals realistically. Some more general systems are researched that can support different kinds of agents (like cars and pedestrians),<ref>{{cite journal |doi=10.1002/cav.1654 |title=Vehicle-pedestrian interaction for mixed traffic simulation |journal=Computer Animation and Virtual Worlds |volume=26 |issue=3–4 |pages=405–12 |year=2015 |last1=Chao |first1=Qianwen |last2=Deng |first2=Zhigang |last3=Jin |first3=Xiaogang }}</ref> different levels of abstraction (like individual and continuum),<ref>{{cite journal |doi=10.1145/2070781.2024169 |title=Interactive hybrid simulation of large-scale traffic |journal=ACM Transactions on Graphics |volume=30 |issue=6 |pages=1 |year=2011 |last1=Sewall |first1=Jason |last2=Wilkie |first2=David |last3=Lin |first3=Ming C. }}</ref> agents interacting with smart objects,<ref>{{cite book |doi=10.1007/978-3-7091-6375-7_6 |chapter=Modeling Objects for Interaction Tasks |title=Computer Animation and Simulation '98 |url=https://archive.org/details/computeranimatio1999poll |url-access=limited |pages=[https://archive.org/details/computeranimatio1999poll/page/n77 73]–86 |series=Eurographics |year=1999 |last1=Kallmann |first1=Marcelo |last2=Thalmann |first2=Daniel |isbn=978-3-211-83257-8 }}</ref> and more complex physical and [[social dynamics]].<ref>{{cite conference |doi=10.2312/SCA/SCA07/099-108 |date=2007 |last1=Pelechano |first1=N. |last2=Allbeck |first2=J.M. |last3=Badler |first3=N.I. |title=Controlling Individual Agents in High-Density Crowd Simulation |conference=Eurographics/Siggraph Symposium on Computer Animation |isbn=978-3-905673-44-9 }}</ref>