Billboarded Cutaway Visualization for Subsurface Urban Sewer Networks - Flood Simulation embedded in Unity3D

Manuel Matusich
Billboarded Cutaway Visualization for Subsurface Urban Sewer Networks - Flood Simulation embedded in Unity3D
[Bachelor Thesis] [image]

Information

Abstract

Visualizing the results of a flood simulation interactively in real-time has become very important due to the increasing number of flood hazards in the recent past. An important part of a flood simulation is the impact on the sewer system of the flooded city. For the simulation itself only a very primitive data structure of a sewer system is required. Therefore this thesis proposes an innovative and efficient technique to render sewage pipes and to visualize the water flow inside of them. With a simple underlying data structure of node positions, billboarded sewage pipes are constructed in the geometry shader. With a proxy geometry the stencil buffer is utilized to distinguish outside and inside of the pipe and the billboards are drawn accordingly. In addition another technique is introduced to cut-open the occluding terrain to expose the sewage pipes to the viewer. Therefore a two dimensional distance transform of the sewer network is generated. The created distance field is used to discard fragments of the terrain, which are relatively close to a pipe. Further an artificial thickness is added to the cut-open terrain analytically in image-space. The techniques are presented in detail and their implementation is demonstrated in Unity3D. It is evaluated by comparing the result to multiple conventions for computer generated cutaways. Additionally the feedback from visualization experts and the technical performance is presented. The results show that billboarded and cut-open tubular geometry can be rendered fast, efficient and with a low memory footprint. Furthermore the technique fulfills many of the design principles for cutaways and got positive feedback from visualization experts.

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BibTeX

@bachelorsthesis{Matusich-2017-01,
  title =      "Billboarded Cutaway Visualization for Subsurface Urban Sewer
               Networks - Flood Simulation embedded in Unity3D",
  author =     "Manuel Matusich",
  year =       "2017",
  abstract =   "Visualizing the results of a flood simulation interactively
               in real-time has become very important due to the increasing
               number of flood hazards in the recent past. An important
               part of a flood simulation is the impact on the sewer system
               of the flooded city. For the simulation itself only a very
               primitive data structure of a sewer system is required.
               Therefore this thesis proposes an innovative and efficient
               technique to render sewage pipes and to visualize the water
               flow inside of them. With a simple underlying data structure
               of node positions, billboarded sewage pipes are constructed
               in the geometry shader. With a proxy geometry the stencil
               buffer is utilized to distinguish outside and inside of the
               pipe and the billboards are drawn accordingly. In addition
               another technique is introduced to cut-open the occluding
               terrain to expose the sewage pipes to the viewer. Therefore
               a two dimensional distance transform of the sewer network is
               generated. The created distance field is used to discard
               fragments of the terrain, which are relatively close to a
               pipe. Further an artificial thickness is added to the
               cut-open terrain analytically in image-space. The techniques
               are presented in detail and their implementation is
               demonstrated in Unity3D. It is evaluated by comparing the
               result to multiple conventions for computer generated
               cutaways. Additionally the feedback from visualization
               experts and the technical performance is presented. The
               results show that billboarded and cut-open tubular geometry
               can be rendered fast, efficient and with a low memory
               footprint. Furthermore the technique fulfills many of the
               design principles for cutaways and got positive feedback
               from visualization experts.",
  month =      may,
  address =    "Favoritenstrasse 9-11/186, A-1040 Vienna, Austria",
  school =     "Institute of Computer Graphics and Algorithms, Vienna
               University of Technology",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2017/Matusich-2017-01/",
}