3D Portrayal Interoperability Experiment - 3D-Stadtmodelle · areas of CAD, AEC, geospatial and 3D visualization, and urban simulation. A variety of products, information and services

3D Portrayal Interoperability Experiment

Benjamin Hagedorn Computergraphische Systeme

Hasso-Plattner-Institut an der Universität Potsdam

Workshop 3D-Stadtmodelle 2011

Bonn, 9. November 2011

OGC & 3DIM

9.11.2011 3D Portrayal Interoperability Experiment | Benjamin Hagedorn | www.hpi3d.de 2

What is the Open Geospatial Consortium?

The OGC

• A non-profit, international voluntary consensus standards organization that is leading the development of standards for geospatial services that support interoperable solutions that "geo-enable" the Web, wireless and location-based services and mainstream IT.

• Facilitates a consensus process in which Members from currently 424 organizations collaborate to define and maintain OGC standards.

• 35 Adopted standards.


http://www.opengeospatial.org

http://www.opengeospatial.org/

Open Geospatial Consortium

The OGC

• The Open Geospatial Consortium (OGC) is an international industry consortium of 421 companies, government agencies and universities participating in a consensus process to develop publicly available interface standards. OGC® Standards support interoperable solutions that "geo-enable" the Web, wireless and location-based services and mainstream IT. The standards empower technology developers to make complex spatial information and services accessible and useful with all kinds of applications.

http://www.opengeospatial.org

3D Portrayal Interoperability Experiment | Benjamin Hagedorn | www.hpi3d.de 9.11.2011 4

Open Geospatial Consortium

The OGC Vision

• To achieve the full societal, economic and scientific benefits of integrating electronic location resources into commercial and institutional processes worldwide.

The OGC Mission

• To serve as a global forum for the development, promotion and harmonization of open and freely available geospatial standards …

Urban Model of Berlin based on OGC CityGML

Source: www.3d-stadtmodell-berlin.de 3D Portrayal Interoperability Experiment | Benjamin Hagedorn | www.hpi3d.de 9.11.2011 5

http://www.3d-stadtmodell-berlin.de/





OGC Domain Working Groups (Aug-8-11)

3D at the OGC

3D Portrayal Interoperability Experiment | Benjamin Hagedorn | www.hpi3d.de

An interest or focus in 3D content modeling, sharing, and integration/fusion

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3D Information Management DWG

The 3DIM Mission

• “A great deal of technical innovation has been accomplished in the areas of CAD, AEC, geospatial and 3D visualization, and urban simulation. A variety of products, information and services abound in each of these environments. This work is of interest to the Geospatial community in that there is a growing need for technologies and information to interoperate flexibly and fluidly between these domains to support a range of vital services and decision support needs. The CAD/GIS WG will focus its efforts on identifying and acting on opportunities to improve interoperability geospatial data and services across these domains.”


3DIM DWG - Overview

3DIM History

• Formed in 2005 as the CAD/GIS Working Group

• Changed name to 3D Information Management Domain Working Group in 2007 to better reflect the diversity of work in the group

• Initiated CityGML Standards Working Group in 2007

• Initiated Oblique Imagery Domain Working Group in 2009

• 3D Portrayal Interoperability Experiment started in May 2011

• IndoorGML Standardization in preparation

Activities

• Devise/Initiate architecture for open interoperable 3D services

• Advance Discussion Papers and Best Practices

• Participate in Testbeds

• Build on industry partnerships


3DIM DWG - Relationships

buildingSMART alliance (MoU)

• Development of IFC, the major, open standard for Building Information Modeling (BIM)

• AECOO-1 Testbed: Discussion Paper released

• BIM-GIS Information Exchange Project

Special Interest Group 3D (MoU)

• German organization responsible for initial CityGML format

• MoU signed

W3C Point of Interest Working Group

• Mission is to develop a technical spec for the representation of "Points of Interest" information on the Web

Web 3D Consortium (MoU)

• X3D: ISO Graphics Standard for 3D on the Web


Service-based 3D Portrayal


OGC 3D Standards

OGC Geography Markup Language (GML)

• XML-based language for encoding geographic information to be stored and transported over the Internet

• Defines both the 2D and 3D geometry and properties of objects that comprise geographic information.

CityGML

• Application independent Geospatial Information Model for virtual 3D city models and 3D landscape models

• Comprises different thematic areas(buildings, vegetation, water, terrain, traffic etc.)

KML Encoding Standard

• XML for geographic visualization on 2D and 3D Earth browsers

• Features for display: placemarks, images, polygons, 3D models, text, etc.


3D Portrayal Services

Separation of rendering concerns; examples of services and formats:

KML

CityGML

X3D

GML

WFS WMS

WVS

W3DS

GoogleEarth

DP

DP

SLD for WMS

X3DViewer


3D Portrayal Services

Missing Link

• Proprietary 3D portrayal solutions available for Perspective Street Views, Virtual Globes (commercial and open source)

• However, extensibility and interoperability are limited and projects (e.g. 3D City Models) depend on the business model of existing platforms

• By opening the 3D portrayal interfaces it becomes possible to exchange servers and clients in a flexible way

• 3D visualization systems have different requirements than full desktop GIS

We need a “Map Server for 3D”


OGC Candidate 3D Portrayal Standards

Web 3D Service and Web View Service


OGC Candidate Standard: Web 3D Service

Web-based, Graphics-Based Provision of and Access to Virtual 3D Worlds

• Geodata is delivered as scenes that are comprised of display elements, optimized for efficient real time rendering at high frame rates

• It can be used for web applications and datasets that are too big for being stored in single files.

• Streaming allows effective fly-throughs.

• All features supported by web 3D standards (VRML, X3D, COLLADA, KML) can be exploited.

www.w3ds.org


http://www.heidelberg-3d.de/


OGC Candidate Standard: Web View Service

Web-based, Image-Based Provision of and Access to Virtual 3D Worlds

• Server-side model management and 3D rendering

• Generation of images of views on the 3D model and transfer to viewer clients

• Provides visual, thematic, and geometric information

• Reduces data complexity and rendering complexity for clients

• WVS is a 3D equivalent of 2D map services


www.webviewservice.org



3DPIE - Setting


3D Portrayal Interoperability Experiment

Main focus on Web 3D Service and Web View Service

• 3DPIE tests server-side issues and client-server interaction to test the interoperability along the visualization pipeline: Advance and harmonize developments of Web 3D Service (W3DS) and Web

View Service (WVS) candidate standards.

Test the applicability of W3DS-based and WVS-based 3D portrayal approaches for different client platforms, including thick clients, web-based clients, and mobile clients.

Test the compatibility of 3D portrayal based on W3DS and WVS with standards-based data formats, including, e.g., CityGML.

Lower the barriers for the implementation, integration, and usage of 3D portrayal capabilities.

http://www.opengeospatial.org/projects/initiatives/3dpie



3DPIE – Context


3DPIE – Questions to Answer

Questions to Answer

1. Can the draft service candidates of WVS and W3DS adequately support the web-based management, portrayal, and exploration of environmental and urban 3D geodata?

2. Can the W3DS and WVS specifications be further harmonized to provide a more common interface to 3D portrayal capabilities and to support their potential integration and combination?

3. What are best practices for the application of the various 3D portrayal approaches, including graphics-based 3D portrayal (e.g., through W3DS) and image-based 3D portrayal (e.g., through WVS)?

4. What are best practices for the application of the various 3D geodata formats and 3D graphics data formats including CityGML, X3D, KML, COLLADA, and others?

5. How to exploit W3DS and WVS from various client platforms, including thin-clients, web-based clients, and mobile clients?


3DPIE – Use Case

„Urban Planning“ as a major Use Case

Examples of using 3D portrayal within the urban planning process:

Demand, Conceptualization

Selection of best submission

Constraints

Decision

Engineering

Construction

Underground Eploration

Public participation

Subsurface Structures, Geology

Architectual competition Urban Development Plan, Zoning

CAD, BIM


3DPIE – Participants

Participants (including 3 Web 3D Cons. members)

• Bitmanagement

• CACI

• Fraunhofer IGD

• GIScience at the University Heidelberg

• Hasso-Plattner-Institut at the University Potsdam

• IGG at Technical University Berlin

• Institute Geographic Nationale (IGN)

• LSIS at Aix-Marseille University

• MOVES Institute at the Naval Post Graduate School

• Virginia Tech

Additionally, many OGC Members are observing the 3DPIE


3DPIE – Workplan

Work Item 1: Data Integration

• Ex. #1A: Import raw data into W3DS

• Ex. #1B: Import raw data into WVS

Work Item 2: Service Integration

• Ex. #2A: Integration of W3DS data in WVS client

• Ex. #2B: Integration of WVS images in W3DS client

• Ex. #3A: Seamless integration of multiple W3DS in a client

• Ex. #3B: Overlay images from multiple WVS in a client

Work Item 3: Service Delivery

• Ex. #4A: Web-based portrayal through W3DS

• Ex. #4B: Web-based portrayal through WVS

• Ex. #5A: Mobile 3D graphics from W3DS

• Ex. #5B: Mobile perspective images from WVS


Architecture

3DPIE Architecture

Data Integration Service Integration, Service Delivery


Schedule

3DPIE Schedule

• Kickoff on 26 May 2011

• Intended duration: 5 months

• Planned to have results ready for the OGC TC Meeting in Brussels in November 2011

June July August September October

Demonstration and

Report

Work Item 1: Data Integration

Work Item 2: Service Integration

Work Item 3: Service Delivery


November

3DPIE – Experiments & Results


Data Integration

Data Formats

• CityGML

• Keyhole Markup Language Geodata description language

OGC Standard since 2008

• Collada XML-based open exchange format for data, e.g., 3D geodata

• X3D


Data Integration

X3D Extensible 3D Graphics Format

• Scenegraph-based 3D graphics data exchange format

• Successor of VRML Standard

• Developed by the Web 3D Consortium (MoU with OGC)

• W3C Standard for 3D content in the Internet

• Variants X3D/VRML

X3D/XML

X3DB (binary X3D)

• Standardized by ISO

• X3DEarth provides a set of geodata-related Nodes:


GeoDoordinate GeoLocation GeoLOD GeoMetadata GeoOrigin GeoPositionInterpolator GeoProximitySensor GeoTouchSensor GeoTransform GeoViewpoint

Data Integration

Paris Data (Bati3D data)

• Extent: ca. 100 sqkm

• CityGML terrain + LOD2 buildings

• Fully textured (Texture Atlases)

• Provided in 446 tiles (500*500 m)


Data Integration

Mainz Data

• Layers Gelaende

Gebaeude (LOD1)

sewage_duct

Mainz data available only through the CityServer3D W3DS

Additional planning data

• Planning data that include additional building that are partially textured buildings

• LOD2 for Münsterplatz in separate layer "MuensterplatzLOD2“


Data Integration

Berlin/Potsdam Data Sets

• Three example data sets “Gasometer”

• 430 Buildings in LOD2

• Textured

“24_24”


• Textured

Potsdam


• Availale as CityGML


Data Integration

OpenStreetMap Data


Data Integration

Data and Servers


IGG W3DS

CityServer3D W3DS

HPI 3D Server WVS

OSM-3D W3DS

Images

KML, Collada, X3D, HTML5

KML

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Berlin Data (CityGML)

Paris 3D (CityGML)

Mainz Data (CityGML)

OSM Data

VRML, X3D, KML

Data Integration

Viewers / Clients


XNavigator

Google Earth

Instant Reality Player

HPI WVS Client

HTML5 Browser

BS Contact Geo Images

KML, Collada, X3D, HTML5

KML, KMZ/Collada

VRML, X3D, KML

Data Integration

Preprocessing and integration of 3D city models

• Preprocessing of the large data sets

• Handling and management of massive 3D city models (large storage required, large file numbers, texture handling)

• Spatial organization and

• Generation of graphical elements

• Rendering of views on large 3D City Models (WVS)


Data Integration

IGG W3DS


Paris 3D (CityGML)

3DCityDB Importer

3DCityDB

3DCityDB Exporter

Tile Cache

KMZ_collada

KMZ_geometry

IGG W3DS

refers to KMZ files through KML-NetworkLinks

KML master file

Data Integration

Paris: Massive Textures

• Need to split Texture Atlases to import into 3DCityDB

• Should textures ind raw data be represented and delivered as texture atlases?


Data Integration

CityServer3D

• Fraunhofer updated CityServer3D to implement W3DS 0.4.0

• Specific operations can be mapped to W3DS operations GetTileDefinition

GetScenario

• Integrated and provided Paris data set

Mainz data


Data Integration

Data Integration Experiments

• Importing Paris data set into IGG Web 3D Service

• Importing Berlin data set into IGG Web 3D Service

• Importing Mainz data set into CityServer3D

• Importing Paris data set into CityServer3D

• Importing Paris data set into HPI WVS

• Processing OpenStreetMap data and importing into OSM-3D


Service Integration & Delivery

Approache for Service Delivery

• An integrated client consumes one or more service capability documents

• File-based integration/combination


Viewer Master File

Service

Service

Service

Client

Service

Service Capabilities

Capabilities

url

url

url

Service Integration & Delivery

Example: Portrayal of Paris data from IGG W3DS


W3DS export to KML and integration with Google Earth

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IGG – W3DS


STYLES=geometry STYLES=textured

Berlin

IGG – W3DS


Paris

small projected region: STYLES=geometry

large projected region: STYLES=textured

IGG – W3DS


Serving Large City Models

Large scale models require

• Spatial organisation of geodata / graphics data

• Streaming this data to a consumer

Fundamental questions

• What does a client know about the spatial organisation of a scene?

• What does a client have to do?

Two approaches for dynamic data integration

• Include knowledge about spatial organization in the data, e.g., as a scene graph Care free package provided to a viewer client

• Provide a specific data tiling mechanisms through service interface



W3DS specific Tiling Mechanism

• W3DS advertises Tiling in metadata document

Master Document with Raster Specification

• A master document refers geometry tiles directly

• Problematically for large scene Worldwide coverage would require a very large raster

Adaptive, Dynamic Refinement

• Special scene graph nodes can group child nodes (group nodes and geometry nodes)



W3DS Tiling Mechanism

• W3DS advertises TileSet element in service meta data document

• Tile are requested via W3DS GetTile operation



GetScene-based transparent Tiling in W3DS

• W3DS KML export via GetScene

• Handling arbitrary bounding boxes in requests

• Based on a layers MaxScaleDenominator

• Client retrieves a valid documents

Example

• MaxScaleDenominator=300

• Requested bounding box is 400 * 500 m

• Results in a quadtree of 4 tiles

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Requested Area Responsed Tiles


GetTileDefinition

• http://host/cs3d/Controller?do=GetTileDefinition&template=entrypoint&surface=mainz_stadt



GeoLOD nodes in X3D

• GeoLOD node provides a terrain-specialized form of the regular LOD node rootUrl or rootNode are used to define geometry shown at default level

child1Url ... child4Url fields define quadtree links to children subscenes

geoSystem defines geospatial coordinate system




<NetworkLink>

<Region>

<LatLonAltBox>

<Lod>

<Link> ... to W3DS, e.g., to GetScene operation

... more NetworkLinks


Tile Generation

• Raster tiles could be created „on the fly“

• Raster tiles could be preprocessed and cached

Impact on W3DS Service Specification.

• Make the implementation of W3DS Tiling mechanism optional

• Use format‘s tiling mechanisms if available


Height References

Dealing with Height References


Height References

Dealing with Height References

• Object locations needs to fit the terrain that is used by a 3D viewer

• Problematically in a distributed 3D portrayal system with distributed and independently generated 3D data

• Approaches Deriving the terrain height, e.g., via Google Elevation API

• Example request: http://maps.google.com/maps/api/elevation/xml?locations=39.7391536,-104.9847034&sensor=false

Use language features to position 3D objects relative to a terrain surface

• KML: Location, e.g., “relativeToHeight”

• X3D: GeoLocation


Further Discussions

• Should we talk about data „layers“ in 3D portrayal or do we rather handle FeatureTypes?

• Features below the terrain are not visible in Google Earth …


WVS-based Visualization

WVS requires Server-side Rendering

• Graphics data needs to be highly optimized

• Fast access to texture data and large memory required for efficient rendering servers


WVS-based server-side 3D rendering

WVS-based Visualization

Displaying WVS imagery in Google Earth


Web-based 3D Portrayal

X3DOM City Viewer im Web Browser


Mobile 3D Portrayal

X3DOM City Viewer im Web Browser


Mobile 3D Portrayal

BS Contact on IOS 5


Mobile 3D Portrayal

WVS-based mobile client


Conclusions

Some of the 3DPIE Results

• Demonstration and discussion of different approaches for 3D geodata processing, integration, and visualization

• New implementation of the IGG W3DS

• CityServer3D was adapted to latest W3DS specification

• Extension of the Xnavigator client to consume multiple W3DS capability documents

• Increasing conformance of service implementation

• Increasing conformance of data format implementations


Conclusions

Next Steps / Future Work

• Tiled WVS?

• Test and further develop feature data access

• How should the GetFeatureData operation work?

• Navigation and Interaction with portrayed data

• Extension of 3DCityDB to export X3D

• W3DS / WVS Standardization ?!


Contact

Benjamin Hagedorn [email protected]

Prof. Jürgen Döllner [email protected]

Computer Graphics Systems Hasso-Plattner-Institut for Software Systems Engineering at University of Potsdam http://www.hpi3d.de

Arne Schilling [email protected] GIScience, University of Heidelberg www.geog.uni-heidelberg.de/giscience.html Volker Coors [email protected] University of Applied Sciences, Stuttgart http://www.hft-stuttgart.de


mailto:[email protected]



http://www.hpi3d.de/








http://www.geog.uni-heidelberg.de/giscience.html






http://www.hft-stuttgart.de/



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3D Portrayal Interoperability Experiment - 3D-Stadtmodelle · areas of CAD, AEC, geospatial and 3D visualization, and urban simulation. A variety of products, information and services