1. Photorealistic 3D SimulationJust pretty gimmicks with limited value?Ho Lok Man (10613082d)LSGI4321 Geo-information for Urban and Regional Studies11/5/2011

2. Table of ContentTable of Content ........................................................................................................................................... 0Table of Figures ............................................................................................................................................. 1Topic 3 ........................................................................................................................................................... 2Abstract ......................................................................................................................................................... 2Background ................................................................................................................................................... 2Usage of photorealistic 3D simulation .......................................................................................................... 5Disadvantages of 3D simulation.................................................................................................................... 5Examples: Using 3D simulation for analysis.................................................................................................. 6 1. Urban Planning and Transportation System Planning and Management ................................... 6 2. Disaster Prevention and Rescue Simulation ................................................................................ 8Conclusion ..................................................................................................................................................... 9References .................................................................................................................................................. 10Table of FiguresFIGURE 1 - A 2D URBAN PLAN. SOURCE: (DESIGN + DEVELOPMENT MANAGEMENT CONSULTING SERVICES , 2011) ........................2FIGURE 2 - A 3D URBAN PLAN. SOURCE: (HALLYUWORLD PROJECTS , 2009)...............................................................................3FIGURE 3 - 2D (UPPER LEFT), 3D (UPPER RIGHT), AND 2.5D (BOTTOM) SIMULATION. SOURCE: (PENNINGA , 2008) ............................3FIGURE 4 - WORLD TRADE CENTER TRANSPORTATION HUB. SOURCE: (SILVERSTEIN PROPERTIES , INC, 2011) ..................................4FIGURE 5 2D GRID-BASED WITH 3D VECTOR MODEL. SOURCE: (E VANS, 2009) ..........................................................................7FIGURE 6 - 3D SIMULATION OF BEHAVIORS OF PEDESTRIAN MOVEMENTS. SOURCE: (CROOKS, HUDSON-S MITH, & PATEL, 2010) ........7FIGURE 7 - FINDING SHORTEST PATH BETWEEN THE FIRE STATION AND THE DISASTER SITE. SOURCE: (KWAN & LEE , 2005) ...................8FIGURE 8 - 3D DUST AND UNKNOWN GAS SIMULATION. SOURCE: (VROEIJENSTIJN & HENDERSON, 2011) .......................................9 3. Topic 3It has been argued that photorealistic 3D simulation is just pretty gimmicks with limited value. Criticallyreview the validity of this statement.AbstractNowadays, photorealistic 3D simulation had been argued that it is just pretty gimmicks with limitedvalue. The validity of this statement will be reviewed critically in this paper. This paper could discuss thetopic by several sections: background of photorealistic 3D simulation, usage of photorealistic 3Dsimulation,the disadvantagesof photorealistic 3D simulation, and followed by some photorealistic 3Dsimulation examples.BackgroundSince many years ago, urban planners use some urban simulation for understanding the cities better.We usually heard of 2D simulation and 3D simulation. Basically, 2D simulation takes place in two-dimensional space, usually drawn with line and a flat background.For 3D simulation, it takes place inthree-dimensional space with objects able to move on three axes.When comparing with 2D simulation and 3D simulation, 2D simulation is simply a plane with some linesand polygons (Figure 1 - a 2D urban plan). However, only professions can understand the meaning of thelines and polygons: maybe some of them are roads, some are building blocks, or some may rivers, withsome agriculture land. Public may not have enough knowledge to understand the maps.Figure 1 - a 2D urban plan. Source:(Design + Development Management Consulting Services, 2011) 4. For the 3D simulation, it is a more fancy and eye-catching simulation. It contains blocks, tubes, sphereetc.;users (both the urban planners and the public) can identify them by the visualized effect. Users caneven rotate it with 180o degrees, or even 360 odegrees, to know more about the plan and the region. By3D simulation, a complex building can be shown in 3D easily instead of just a few lines and polygons. A3D simulation can show more details, as in Figure 2 - a 3D urban plan. Source: (HallyuWorld Projects,2009).Figure 2 - a 3D urban plan. Source: (HallyuWorld Projects, 2009)For additional information, actually, there are numerous types of simulation. Apart from 2D simulationand 3D simulation, there is one called 2.5D simulation. 2.5D simulation uses two-dimensional methodsto create an illusion of 3D graphic, and it also called as pseudo-3D rendering(Sanders, 2011). Thatmeans, 2.5D simulation is similar to 3D simulation, but no rotation can be done for the model.Theillustration of differences between 2D, 2.5D and 3D are as follows (Figure 3 - 2D (upper left), 3D (upperright), and 2.5D (bottom) simulation. Source: (Penninga, 2008): 5. Figure 3 - 2D (upper left), 3D (upper right), and 2.5D (bottom) simulation. Source: (Penninga, 2008)Also, there is one called photorealistic 3D simulation. It is a kind of 3D simulation that aims to makethe model as real as the reality(Boddy-Evans, 2011), by using shading, texturing, and lighting.Bytexturing with photos, the photorealistic 3D simulation will become more realistic than a normal 3Dmodel. Apart from that, a photorealistic 3D simulation can simulate the effects of light source, shadows,winds, motivation of trees, sea shore, dust in the road, fires etc.Thus in the ideal case, if taking screen captures from a photorealistic 3D model, that screen capturewould be looks like a photo taken from a scene, or even having more details than a normal photo. Thefollowing figure is an example of a screen capture photorealistic 3D model (Figure 4 - World TradeCenter Transportation Hub. Source: (Silverstein Properties, Inc, 2011)). As we can see, this modelinvolves details of the main buildings. This screen capture is looks like a photo, but it actually still inconstruction in New York until the quarter of 2014. Also, as we can see, by the usage of shadows, lightsources, the 3D models become more realistic. 6. Figure 4 - World Trade Center Transportation Hub. Source: (Silverstein Properties, Inc, 2011) 7. Usage of photorealistic 3D simulationPhotorealistic 3D simulation is mainly used for simulating a 3D digital city. It has good potentialapplications, from simply displaying data or 3D maps, to huge, complex integrated applications, such asvirtual city tour, urban planning, transportation system planning and management, disaster preventionand rescue simulation, environment and landscape simulation, project planning and evaluation,Location-Based Services (LBS), 3D navigation, digital archives, building and reconstruction of ruins orspecific scenarios, military and national security, entertainment and game industry etc.(Choi & Chan,2010, p. 26).By photorealistic 3D simulation, apart from the building blocks, trees or roads can be simulate, thesound, wind and dust, rainfall and water, fire and smoke, light and shadow, sun and moon, or even thetraffic flow can be simulated like the real world. These characteristics of 3D simulation enhance thevisual effect, and shorten the analysis speed for decision makers, as they can directly seeing the 3Dmodels and visualized results.For the later sections, the usage of photorealistic 3D simulation in urban planning, transportationsystem planning and management, and the disaster prevention and rescue simulation will be discussedwith examples.Disadvantages of 3D simulationSome criticizers may criticize that, 2D may enough for decision making, as decision makers may only bethe professionals. Public may not need to know the details of the planning projects, or other informationof the land. So, they may ask: do details really a matter? Photorealistic 3D simulation involves hugeamount of data, and the time cost of rendering is very high. By adding light source and shadows, a largeamount of complex computation will be involved. It increases the time used in rendering 3D models.In general, the market price for a high definition (HD) 3D rendering will cost between US$1000 andUS$2000 for one single still image (Jironomo Visualization, 2010). The cost of generating a 3Danimation would be even much higher. This high price is due to long time rendering and many expertsinvolved in the 3D rendering. Thus, when comparing to 2D simulation, the cost of 3D simulation wouldbe much higher.Also, as 3D simulation involved a large amount of data, the cost of maintaining would berelatively higher than maintaining a 2D simulation database.Due to these reasons, some may criticize that 3D simulation is not worthy and with limited value.However, by the following section, the examples will be verifying this statement. 8. Examples: Using 3D simulation for analysisApart from visualization, 3D simulation is always beneficial for analyzing.When doing the urban planning,transportation system planning and management, and the disaster prevention jobs, the benefits of using3D simulation were maximized. In this section, two parts would be discussed: 1. photorealistic 3Dsimulation in urban planning and transportation system planning; 2. Disaster prevention and rescue byphotorealistic 3D simulation.1. Urban Planning and Transportation System Planning and ManagementPhotorealistic 3D simulation is very useful for urban planning. Apart from visualizing the details partsof the cities, or the building blocks, the 3D models can even simulate the wind direction andlightsource for enhancing the analysis process.For wind direction simulation, it is very important for urban planning. It is because the urban climateis mainly determined by the limitation of air exchange (Barlag & Kuttler, 1990/1991). In day time,the hottest part of a city would be the building tops. If these heatsadding with the heat emitted bythe pollutants cannot be dispersed appropriately, it will raise the environmental impact on theresidential population. Thus, air paths are essential for a well-planned and well-balanced city.This is the case in Hong Kong too. According to the urban design guidelines released from thePlanning Department in Hong Kong (2006), Hong Kong needs more winds for thermal relief andcomfort in the built environment. It is because Hong Kong has the subtropical climate with a veryhot and humid summer, air paths are becoming more important than in other countries. To ensurethe new city plan introduces enough wind to the urban areas, a wind direction simulationis veryuseful.Mathematically, the climate and meteorological models are usually in grid-based. However, the citymodels are vector based (Evans, 2009), and a vector based analyze would be resulting a moreaccurate results (Figure 5 2D grid-based with 3D vector model. Source: (Evans, 2009)).Thus, using3D models in vector format to simulate the wind direction is much better when comparing to usethe 2D simulation. It is because the 2D simulation is normally using the grid based system to carryout the wind direction analyzed.Also, for the light source simulation, it is important for urban planning too. In European cooperationproject, there is one project called POLIS. It aims to utilize the solar energy European cities byimplementing strategic town planning and local policy measurements (ISPOL, 2011). Solar energy ishighly depends on the brightness of the sun light. Apart from that, the orientation and availability ofthe area would also affect the reception of the passive solar energy. Through 3D simulation, the 9. light source of the study area could soon be identified, and the amount of light that can receive fromthe area could then be calculated easily. The 3D simulation eases the site selection of solar energy.Figure 5 2D grid-based with 3D vector model. Source: (Evans, 2009)For the transportation system planning and management, photorealistic 3D simulation cansimulates the traffic flow to enhance the analysis process. As thinking of the mass transit railwaysystem is shut down for one week without any pre-notice, the transport system in Hong Kong willresults? As an expert in the transportation system planning and monitoring, he must monitor themovements and keep the traffic flows moving under these circumstances(WINSLOW , 2005). A 3Dsimulation simulating the traffic flow, or the behaviors of pedestrian movements (Figure 6 - 3Dsimulation of behaviors of pedestrian movements. Source: (CROOKS, HUDSON-SMITH , & PATEL, 2010))could be very useful for the administrator make decisions when using a complete visualization inreal time.Figure 6 - 3D simulation of behaviors of pedestrian movements. Source: (CROOKS, HUDSON-SMITH , & PATEL, 2010) 10. 2. Disaster Prevention and Rescue Simulation Photorealistic 3D simulation is very useful for disaster prevention and rescue simulation too. It is because by using 3D models, the situations of having fires, smokes, flooding, or dust can be simulated. For an example, by using 3D simulation, if there is a site having fire, the 3D model can immediately generate the shortest path between the entrance of the site and the disaster site. In 3D simulation, the shortest path uses a modified Dijkstras algorithm that can operates on the 3D network. According to Kwan and Lee (2005), using this integrated 3D network saves more than 1/3 of the travel time, for reaching the disaster site. If shorten the rescuing time, more life in the disaster site can be saved. Figure 7 - Finding shortest path between the fire station and the disaster site. Source: (Kwan & Lee, 2005) Apart from enhancing the quality of real time decision, photorealistic 3D simulation can also be a training tool. The 3D models can have a space-time prediction and shows the potential affected area(ZHENG& YANG, 2011). Also, the 3D models can simulate fake situation, which can help training the decision makers. Unlike the real world, life would not be lost if any wrong decision made. Users can customized the 3D model, by simulating different kinds of disasters, to train the ability of the users emergency decision making. The training may speed up the decision making time when the real disaster comes to the real world. The following figureillustrates an emergency case that the road is full of dust and unknown gas (Figure 8 - 3D dust and unknown gas simulation. Source: (VROEIJENSTIJN& HENDERSON, 2011)). 11. Figure 8 - 3D dust and unknown gas simulation. Source: (VROEIJENSTIJN & HENDERSON, 2011)ConclusionIn conclusion, photorealistic 3D simulation is not only a gimmick. 3D simulation is more realistic than 2Dsimulation, which helps for analysis by visualization. 3D simulation is always being customized, and fitthe users needs. As the simulation is dynamic, users can walk or fly through the study area, and letthem understand the area better.3D simulation is most useful in the urban planning, transportation system planning, disaster preventionand the rescue simulation. It is because 3D simulation can simulates the wind direction, light sources,traffic flow, fire, smokes, flooding, dust, or other natural environment. These characteristic enhancesthe reality of the 3D models.Also, because of the complexity of the real world, this kind of visualization speeds up the time ofdecision making. Planners and decision makers can easily make decisions or plans by simply seeing theeffect of the model. Apart from the town planners and the decision makers, the public can involve intothe town planning process, as users could find easier to understand when using 3D simulation. 12. ReferencesBarlagA.-B., & KuttlerW. (1990/1991). Energy and Buildings. Netherlands: Elsevier Sequoia.Boddy-Evans, M. (2011). Photorealism: Whats the Point? -- Painting Photorealism. Retrieved 10 21, 2011, from About.com: http://painting.about.com/od/paintingforbeginners/a/photorealism.htmChoi, F., & Chan, L. (2010, 3). . , 18-30.CrooksA.T., Hudson-SmithA., & PatelA. (2010). Building 3D Agent-Based Models for Urban Systems.Working Papers Series ( paper 161). LKondon: UCLCASA.Design + Development Management Consulting Services. (2011, 12 7). 3D P3. Dubai, Arabian Peninsula,United Arab Emirates (UAE).EvansStephen. (2009). 3D cities and numerical weather prediction models; An overview of the methodsused in the LUCID project. Working Papers Series ( paper148). London: UCL-CASA.HallyuWorld Projects. (2009, 1 1). Urban Entertainment Center. Suwon, Gyeonggi, China.HKSAR. (2006, 7 1). Chapter 11: Urban Design Guidelines. Retrieved from Planning Department: http://www.pland.gov.hk/pland_en/tech_doc/hkpsg/full/ch11/ch11_text.htm#9ISPOL. (2011, 11 1). POLIS. Retrieved from POLIS: http://www.polis-solar.eu/Jironomo Visualization. (2010 4 17 ). How much does a 3d rendering cost? jironomo.com: http://jironomo.com/architectural-visualisation-blog/2010/04/how-much-does-a-3d-rendering-cost/Kwan, M.-P., & Lee, J. (2005). Emergency response after 9/11: the potential of real-time 3D GIS for quick emergency response in micro-spatial environments. (Vol. 29). (E. a. Computers, Ed.) Ohio, USA: Elsevier.Penninga, F. (2008, 6 18). 3D Topography. A Simplicial Complex-based Solution in a Spatial DBMS. Geodesy 66, pp. 11-16.Sanders, A.-L. (2011). What is 2.5D Animation? Retrieved 11 4, 2011, from About.com guide: http://animation.about.com/od/faqs/f/What-Is-2-5d-Animation.htmSilverstein Properties, Inc. (2011, 10 12). Transportation Hub || About the WTC || World Trade Center ||. New York, New York, United States of America. 13. VroeijenstijnKoen, & HendersonD.Ronald. (2011 8 7 ). Simulating Massive Dust in Megamind.DreamWorks Animation, 1.Winslow, L. (2005, 4 4). 3D Modeling in Transportation Flows. Retrieved from EzineArticles.com: http://ezinearticles.com/?3D-Modeling-in-Transportation-Flows&id=25641Zheng, K., & Yang, Y. (2011, 8 4). The intelligent space-time prediction and analysis of the 3D loess slopegeological disaster based on GIS. Retrieved 11 4, 2011, from IEEE Xplore:http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5959270