3D Building Modelling within the City of Cape Town...In 3D computer graphics, 3D modelling is the process of developing a mathematical representation of any three dimensional surface

3D Building Modelling within the City of Cape Town

20 Nov 2014 Thomas Reiner - Geospatial Services

3D City Models

• Background

• Definition

• Benefits

• Technical / Standards / Specs

• Viewing and Analytical Software

• Workflows

• Current Audit of 3D buildings

• Demonstration / Examples

• Future

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Background

Background – International practice

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Rome - Constantine Era

Scale Model of

Historic Jerusalem

Background – International practice

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Background – Local application

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Note: Mayor,

Cllrs and high

level officials

Background – Digital Model of CBD

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Atlantic Seaboard

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Definition – Computer Graphics

In 3D computer graphics, 3D modelling is the process of

developing a mathematical representation of any three

dimensional surface or object via specialised software. The

product is called a 3D model.

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Power of Visualisation

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Benefits

Benefits

• Visualisation (A picture says a thousand words)

• Simplifies complex situations

• Stakeholder Engagement

• Context

• Better decision making

• Scenario Modelling

• Historical and Event Reconstruction

• Analysis (Zoning, Transport Routes……..)

• Simulation (Flooding)

• Real time inputs (Traffic)

• Effective Communication

• Cost and Time saving

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Height Analysis – Voortrekker Road Corridor

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Line of Sight Analysis

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Transient Shadow Study

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Before and After Study

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Solar Potential Sustainability Planning

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Zoning Analysis

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Technical

Essential elements and considerations for creating a 3D

City Model

• Surface Model

• 3D Object (Building, Roads….)

• Capture Methodology

• Data formats and storage

• Viewing and analysis software and hardware

• Accuracy

• Level of detail required

• Cladded versus non-cladded

• Outside Stakeholder requirements

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LoD – Level of Detail

• LoD 0 Essentially a two and a half dimensional digital terrain model over which an image may be draped

LOD – Level of Detail

• LoD 1 A block model comprising prismatic building with flat roofs.


• LoD 2 A block model with differentiated roof structures and thematically differentiated surfaces.


• LoD 3 Detailed model with exact wall and roof structures, balconies, bays and projections. Textures can be added to these

structures.


• LoD 4 LOD3 with interior structure (floors and rooms, hanged ceilings).

Walk through models.

Standards

• Facility Management: - DIN 276 2006: Cost estimates for buildings - DIN 277 2005: Estimate of floor areas and volumes - Definitions

• ISO Norms: - ISO 19107: Spatial Schema / Boundary Representation - ISO 19109: Feature classes / semantic model • AAA Spatial Schema 3D(Version 7.0 by 2018) – incorporates ISO norms:

- defines standards for application schema, feature catalogues and exchange interfaces • Open Geospatial Consortium (OGC) published CityGML 2.0 (2012), 3.0, 3.2: - City Geography Markup Language (GML) Encoding Standard

- defining representation and exchange of 3D information - geometric / topological model (What – When – How), geometry primitives - semantic (thematic) model (Where - Dimensions), feature classes - Modules: Appearance, Building, CityFurniture, CityObject Groups, Generics,

LandUse, Relief, Transportation, Vegetation, Waterbody


Viewing and Analytical Software

Viewing and Analysis Software

Available to City of Cape Town

• Oblique Imagery System

• ESRI ArcScene – Part of ArcGis Deployment – Enterprise Licence

• ESRI ArcGlobe – Part of ArcGis Deployment – Enterprise Licence

• ESRI City Engine – Separate Installation – Enterprise Licence

• Trimble Sketchup – Free and Professional version

• Google Earth – Free and Professional version

• Specialised Analysis and modelling - E.g. Autodesk Studio Max, K2Vi

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ArcScene


ArcGlobe


City Engine

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Workflow

Flow Chart - Geospatial Data Integration and Methodology


GIS Spatial Data Lidar Point Cloud

Aerial Imagery Stereo Pairs

Terrestrial Survey Data

DTM Ortho Photo

3D Object Additional

Data

Basic 3d Model

QA

Final Model External

Products – 3d Basics


Building Footprints 3d Building Models and

Objects

Building Footprints


Current Audit of 3D Buildings

Current audit of 3D models

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Proposed Capture 2014/2015

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Pilot Study Area – Bellville Station – Metropolitan Transport

Node

• Transport modelling Area


Potential 3D models from historical mapping

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Demonstration/Examples

Aerial Image


Aerial Image with underlying Elevation Model


3D as-built buildings added -Cladded


3D as-built buildings added- Non Cladded


3D as-built buildings – with 3d Zoning Parcels


Proposed Development


Analysis


Example Bellville Pilot Area – Loading of 3D models


















Future

Breaking models into individual floors


Thank You

For queries contact ([email protected])



Documents

3D Building Modelling within the City of Cape Town...In 3D computer graphics, 3D modelling is the process of developing a mathematical representation of any three dimensional surface