Enabling numerical Simulations in semantic 3D City Models using CityGML
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Transcript of Enabling numerical Simulations in semantic 3D City Models using CityGML
Enabling numerical Simulations in semantic 3D City Models using CityGML
13th South East Asian Survey Congress, Singapore
Arne Schilling Stefan Trometer
virtualcitySYSTEMS GmbH CADFEM GmbH
Berlin, Germany Grafing, Germany
Arne Schilling, virtualcitySYSTEMS , SEASC 2015 2
Geoportal Solutions
What is Urban Simulation?
Challenge
Project 1 – Urban Air Flow
Project 2 – Urban Blast Simulation
Discussion
Outline
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What is Urban Simulation?
Simulation of physical phenomena in urban environments using virtual mockups / 3D city models
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What is Urban Simulation?
Mechanical simulations of building structures
Acoustic studies / blast simulations
Wind field simulations
Simulation of flood events
…
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GIS is not designed for performing complex physical computations
• Strengths of GIS are data management, spatial analysis and visualization
• 3D city models are created using remote sensing and automatic feature extraction methods, not using CAD software
Challenge
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Challenge
GIS is not designed for performing complex physical computations
• Strengths of GIS are data management, spatial analysis and visualization
• 3D city models are created using remote sensing and automatic feature extraction methods, not using CAD software
Physical simulations are frequently done in product design
• Using Computer Aided Design (CAD) and Computer Aided Engineering (CAE) software such as ANSYS
• Based on the Finite Element approach -> Numerical Simulation
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Challenge
GIS is not designed for performing complex physical computations
• Strengths of GIS are data management, spatial analysis and visualization
• 3D city models are created using remote sensing and automatic feature extraction methods, not using CAD software
Physical simulations are frequently done in product design
• Using Computer Aided Design (CAD) and Computer Aided Engineering (CAE) software such as ANSYS
• Based on the Finite Element approach -> Numerical Simulation
Technological gap between GIS and CAE Worlds
• CityGML cannot be loaded by CAE software (e.g. ANSYS). Geometrical representations are very different -> we need conversion tools
• Requirements on data quality are different
• Simulation results are mostly stored in proprietary formats
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Challenge
Create a workflow from 3D Geographic Information Systems to Simulation frameworks and back
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Simulating the wind flow in urban environments for calculating pedestrian comfort levels
Collaboration with IDAC Ltd.
Part of Environmental Impact Assessment
Project 1 - Urban Air Flow
Partners
Pedestrian comfort at ground level (streamlines)
Velocity contours at a height of 7m and 150m
Novosibirsk State University of Architecture and Civil Engineering
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Data set: Frankfurt a.M. Germany: many high rise buildings
Approach: Computational Fluid Dynamics (CFD) analysis
Typical wind loads described by velocity profiles were applied
The Navier-stokes equations were solved along with the 𝑘−𝜀 turbulence model.
The analysis was performed using ANSYS CFX “high-performance, general purpose fluid dynamics program”
Project 1 - Urban Air Flow
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From http://www.ansys.com
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Data Link - Geometry Processing Format Conversion from CityGML to STEP
Recreation of geometry and topology
Error detection and Geometry healing
• no self intersections
• no non-manifold geometries
• no interior surfaces
• no holes (“watertight”)
• no stray elements
Defeaturing
Project 1 - Urban Air Flow
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Geometry healing, e.g. removing inner surfaces (top) and resolving self-intersections (bottom)
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Numerical Computations Meshing -> ca. 43 Mio. elements
Setting physical properties (e.g. air density)
Boundary conditions
Running CFD solver
Project 1 - Urban Air Flow
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Presentation Cross sections
Coloring 3D city model
Charts (velocity contours) for reporting
Project 1 - Urban Air Flow
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Background Unexploded bombs from WW2
Safety perimeters must be set up quickly
Critical infrastructure facilities in the area must be determined
Project 1- Urban Blast Simulation
Safety perimeters (red: evacuation, blue: curfew)
Recovery of defused bomb
Disposal of defused bomb
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Approach Data exchange using STEP
Geometry processing (healing)
Shockwave propagation using AUTODYN and APOLLO solvers
Reintegration of simulation results in 3D city model
Project 1- Urban Blast Simulation
Partners
Funding
Web-Interface for visualization of numerical results
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Project 1- Urban Blast Simulation
Partners
Funding
Fast solution by the APOLLO Blastsimulator in cooperation with the Fraunhofer EMI
Objectives Easy accessibility to decision-makers (fire fighers, police, bomb
disposal units etc.)
Integrated and automatic workflow for scenario definition, numerical simulation and presentation of results
Derivation of damage indicators (e.g. broken windows, masonry)
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Project 1- Urban Blast Simulation
Partners
Funding
Derived detailed building models from city models
Analysis and optimization of detailed structural members
H
h
R
x
z
Source: GEORES (www.geores.de)
Further Research Investigate vulnerability of buildings to blasts (simulate structural
damages) -> planning purposes
Increase the resilience of facilities to terroristic threats
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Restrictions • CityGML LOD 2 city models (no windows, balconies etc, roof information), no
information on interior structures
• Simulated area limited to 1x1km (limitation in ANSYS)
• STEP CAD models are not geo-referenced, extension required
Discussion
Steady-state air flow LOD3 model
Super-detailed structural simulation
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Discussion
Benefits • Solution can be added to existing Spatial Data Infrastructures
• Solution relies on open standards (CityGML, OGC services) and industry standards (STEP)
• Data is stored and managed in a central data repository (Oracle, PostgreSQL)
• Will be possible to reintegrate simulation results into 3D city model database (damage indicators, wind loads)
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Current Technology Partners
Urban Simulation Network
Urban Simulation
&
Urban Blast Protection
Flooding & Tsunami Protection
Urban Air Flow
Smoke & Pollution Development
Crowd Movement
Novosibirsk State University of Architecture and Civil Engineering
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Conceptual Approach
ETL processes
Open architecture • Other applications can be
plugged into / connected to the 3D SDI
virtualcitySYSTEMS 2015
Thank You Arne Schilling Stefan Trometer
virtualcitySYSTEMS GmbH CADFEM GmbH
[email protected] [email protected]
http://www.virtualcitysystems.de http://www.cadfem.de