3D Geo-standaarden workshop

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3D Geo-standaarden workshop

  1. 1. Workshop 3D standaarden 24 Juni 2010
  2. 2. Diversen… <ul><li>3D: </li></ul><ul><ul><li>BReps (Semantisch niveau) </li></ul></ul><ul><ul><li>Normaal vectoren </li></ul></ul><ul><ul><li>CSG / Boolean opp. </li></ul></ul><ul><ul><li>Primitieven </li></ul></ul><ul><li>Standaarden: </li></ul><ul><ul><li>DXF </li></ul></ul><ul><ul><li>SHP </li></ul></ul><ul><ul><li>VRML </li></ul></ul><ul><ul><li>X3D </li></ul></ul><ul><ul><li>KML / KMZ </li></ul></ul><ul><ul><li>Collada </li></ul></ul><ul><ul><li>WebGL </li></ul></ul><ul><ul><li>O3D </li></ul></ul><ul><ul><li>CityGML </li></ul></ul><ul><ul><li>IFC </li></ul></ul>
  3. 3. 3D algemeen - BRep
  4. 4. 3D algemeen – Extruded Solid
  5. 5. 3D algemeen - Cube
  6. 6. 3D algemeen – Normaal Vectoren
  7. 7. 3D algemeen – CSG (Boolean Oper.)
  8. 8. 3D algemeen - Primitieven
  9. 9. 3D Standaarden
  10. 10. Industrial standards: DXF <ul><li>DXF ( Drawing Interchange Format) created by Autodesk, December 1982 as part of AutoCAD 1.0 </li></ul><ul><li>Support many different geometries, layers and drawing attributes </li></ul><ul><li>Does not support thematic attributes </li></ul><ul><li>Specifications for DXF from AutoCAD Release 13 (November 1994) to AutoCAD 2008 (March 2007) on the web site </li></ul>http://www.autodesk.com/techpubs/autocad/acad2000/dxf/index.htm
  11. 11. Industrial standards: ESRI SHP <ul><li>Created by the Environmental System Research Institute (ESRI). </li></ul><ul><li>point, multi-point, polygon, polyline and multi-patches. </li></ul><ul><li>SHP adapted for faster drawing speed and editing capabilities. </li></ul><ul><li>Contains thematic attributes </li></ul><ul><li>Consists of three files: </li></ul><ul><li>Main file: *.shp Index file: *.shx DBase file: *.dbf </li></ul>http://esri.com/library/whitepapers/pdfs/shapefile.pdf
  12. 12. Disadvantages <ul><li>Need to be accepted by other vendors </li></ul><ul><li>Vendors provide new versions </li></ul><ul><li>Not for visualisation on Internet </li></ul>
  13. 13. Virtual Reality Modelling Language (VRML) <ul><li>Started in 1995, 1997 accepted as a standard </li></ul><ul><li>Web standard for exchange of graphics </li></ul><ul><li>Language for modelling 3D realistic scenes and interaction </li></ul><ul><li>ASCII file format </li></ul>
  14. 14. VRML basics <ul><li>Nodes for all </li></ul><ul><li>scene components: </li></ul><ul><li>3D Geometry </li></ul><ul><li>Lights </li></ul><ul><li>Shading </li></ul><ul><li>Colours </li></ul><ul><li>Texture (draping and mapping) </li></ul><ul><li>camera </li></ul><ul><li>+ behaviour </li></ul>
  15. 15. VRML many possibilities to design a scene (e.g. nodes ) <ul><li>http://www.web3d.org/technicalinfo/specifications/vrml97/part1/nodesRef.html </li></ul><ul><li>3D Geometry – points, extruded shapes </li></ul><ul><li>Lights – background, point, directional lights </li></ul><ul><li>Shading – normal vectors </li></ul><ul><li>Texture – draping </li></ul><ul><li>View – several view points </li></ul><ul><li>Fog, billboard </li></ul><ul><li>Grouping nodes – group </li></ul><ul><li>Transform – rotate, scale, translate </li></ul><ul><li>Inline – link to another node </li></ul><ul><li>Sensors – to sense user actions </li></ul><ul><li>Routes – to pass the action to another node </li></ul><ul><li>Scripts – Java, Javascript </li></ul>
  16. 16. VRML creating and editing the file (VR modellers)
  17. 17. VRML: mostly used for visualisation <ul><li>Good visualisation results in large files (gzip) </li></ul><ul><li>Simple visualisation is ‘too schematic’ </li></ul><ul><li>Inventor – file format (not XML) </li></ul><ul><li>Thematic (semantic info) cannot be stored </li></ul>
  18. 18. X3D <ul><li>Web3D Consortium </li></ul><ul><li>Based on XML and Open Inventor </li></ul><ul><li>More possibilities for visualization and interaction </li></ul><ul><li>Extensions for various purposes: X3D Core, X3D Interchange, X3D CAD, X3D Geospatial and X3D Immersive </li></ul><ul><li>Browser makers can define their own extensions and submit them for standardisation by the Web3D Consortium . </li></ul>http://www.web3d.org/x3d/specifications/x3d/
  19. 19. X3D <ul><li>Few browsers </li></ul><ul><li>No export from CAD and GIS vendors (developing own web applications) </li></ul><ul><li>No standardised thematic information (semantics) </li></ul>
  20. 21. Keyhole Markup Language (KML) <ul><ul><li>Developed by the company Keyhole (bought by Google) Google brought KML into OGC </li></ul></ul><ul><ul><li>Goals according to the specification document: </li></ul></ul><ul><ul><li>Language for presentation of geographic features and annotations (geographic coordinates) </li></ul></ul><ul><ul><li>Web-based online maps (2D) and digital globes (3D). </li></ul></ul><ul><ul><li>Focus on visualization and user interaction </li></ul></ul><ul><ul><li>No semantics </li></ul></ul>
  21. 22. KML <ul><ul><li>KML supports </li></ul></ul><ul><ul><ul><li>georeferenced images and 2D and 3D shapes in different styling options </li></ul></ul></ul><ul><ul><ul><li>definition of pictograms and textual markers </li></ul></ul></ul><ul><ul><ul><li>association of HTML and other content with the shapes </li></ul></ul></ul><ul><ul><ul><li>geographic embedding of 3D computer graphics models (e.g. COLLADA, X3D) </li></ul></ul></ul><ul><ul><li>KML is not based on ISO 191xx standards </li></ul></ul>
  22. 24. COLLADA <ul><ul><li>COLLA borative D esign A ctivity: Open Standard, KHRONOS Group </li></ul></ul><ul><ul><li>generic, extensible format for 3D digital contents creation </li></ul></ul><ul><ul><li>design background: computer graphics and gaming </li></ul></ul><ul><ul><li>good representation of 3D geometry and appearance (since V1.4 supported of topology) </li></ul></ul><ul><ul><li>strong appearance and physics models (shaders, animation, ragdolls) </li></ul></ul><ul><ul><li>no explicit support of semantics and (up to V1.4) no georeferencing </li></ul></ul><ul><ul><li>Beheerd door Kronos groep </li></ul></ul>
  23. 25. WebGL <ul><li>3D Web standaard </li></ul><ul><li>Javascript implementatie </li></ul><ul><ul><li>Géén plugin nodig </li></ul></ul><ul><ul><li>Hardware acceleratie via grafische kaart </li></ul></ul><ul><li>Binding voor JS om OpenGL ES aan te roepen </li></ul><ul><li>Net als Collada: Kronos groep </li></ul>
  24. 26. O3D <ul><li>Van Google </li></ul><ul><li>Binaire representatie </li></ul><ul><li>Browserplugin nodig </li></ul><ul><li>Gestart omdat WebGL JavaScript gebaseerd is </li></ul><ul><li>Gestopt omdat dat toch goed bleek…. </li></ul>
  25. 29. CityGML <ul><li>Content / Entities: </li></ul><ul><li>Digital Terrain Model / Relief </li></ul><ul><li>Land Use </li></ul><ul><li>GenericCityObject </li></ul><ul><li>Sites </li></ul><ul><ul><li>Buildings </li></ul></ul><ul><ul><li>Bridges </li></ul></ul><ul><ul><li>Tunnels </li></ul></ul><ul><ul><li>Walls </li></ul></ul><ul><ul><li>Landfills </li></ul></ul><ul><ul><li>Excavations </li></ul></ul><ul><li>Transportation objects </li></ul><ul><ul><li>Streets </li></ul></ul><ul><ul><li>Railways </li></ul></ul><ul><li>Water bodies </li></ul><ul><li>Vegetation objects </li></ul><ul><li>City furniture </li></ul><ul><ul><li>e.g. street lights, traffic lights, benches </li></ul></ul>
  26. 30. Important features <ul><li>Semantics </li></ul><ul><li>Object parts are modeled as features </li></ul><ul><ul><li>can be assigned thematic attributes </li></ul></ul><ul><li>Geometric-topological model </li></ul><ul><li>Recursive aggregation of objects and geometries </li></ul><ul><li>Textured surfaces </li></ul><ul><li>Subsurface objects </li></ul><ul><ul><li>tunnels, pedestrian underpasses </li></ul></ul><ul><li>Generic concept for external references </li></ul><ul><ul><li>every object can have a link to external resources </li></ul></ul><ul><li>Multi-scale model: five levels of detail (LoD 0-4) </li></ul>
  27. 31. CityGML: semantic and geometric model Courtesy T. Kolbe
  28. 32. Semantics and geometry <ul><li>KML </li></ul><ul><li>Multipatch </li></ul><ul><li>CityGML </li></ul>
  29. 33. Semantics and geometry <ul><li>No defininitions of the objects </li></ul><ul><li>Very general attrtibutes (type, use, ...) </li></ul><ul><li>Until recently only undeground </li></ul><ul><ul><li>Cables and pipes </li></ul></ul><ul><ul><li>Tunnels </li></ul></ul><ul><li>Geometries as in GML (or DBMS if data model) </li></ul><ul><li>One object (feature) may have several geometric representations </li></ul>
  30. 34. Topology/Validity <ul><li>Rules are recommended </li></ul><ul><li>Validity is not checked </li></ul><ul><li>No specific topological data structure </li></ul><ul><li>(in the GML version) </li></ul>
  31. 35. Important concept: Levels of Detail LOD 4 (Walkable) LOD 1 (Block-roof) LOD 2 (Block+roof) LOD 3 (Architectural envelope)
  32. 36. Example: Building in CityGML <ul><li><Building gml:id=“Building0815&quot;> .................. </li></ul><ul><li><lod2SolidProperty> </li></ul><ul><li><gml:Solid srsName=&quot;urn:adv:crs:ETRS89_3GK2-h&quot;> </li></ul><ul><li><gml:exterior> </li></ul><ul><li><gml:CompositeSurface> </li></ul><ul><li><gml:surfaceMember> </li></ul><ul><li><gml:OrientableSurface orientation=&quot;+&quot;> </li></ul><ul><li><gml:baseSurface> </li></ul><ul><li><gml:Polygon> </li></ul><ul><li><gml:exterior> </li></ul><ul><li><gml:LinearRing> </li></ul><ul><li><gml:pos >1.0 1.0 0.0</gml:pos> </li></ul><ul><li><gml:pos >3.0 1.0 0.0</gml:pos> </li></ul><ul><li>.......................... </li></ul><ul><li></gml:LinearRing> </li></ul><ul><li> ..................... </li></ul><ul><li>< /lo d2SolidProperty> </li></ul><ul><li>< / Building> </li></ul>Courtesy T. Kolbe
  33. 38. IFC <ul><li>Semantic, topology, geometry, attributes and relations </li></ul><ul><li>Geometry: </li></ul><ul><ul><li>CSG / Boolean operations </li></ul></ul><ul><ul><li>Solids </li></ul></ul><ul><ul><li>Semantic Geometry! </li></ul></ul>
  34. 39. Hoe ziet het eruit? www.ifcbrowser.com
  35. 41. IFG <ul><li>Afspraak over semantische uitbreiding van IFC </li></ul><ul><li>Voor Georeferentie </li></ul><ul><li>Weinig toegepast in de praktijk </li></ul>
  36. 42. Conclusie
  37. 43. 3D standaarden conclusie <ul><li>Veel standaarden voor representatie </li></ul><ul><li>CityGML en IFC hebben semantiek als meerwaarde!! </li></ul><ul><li>Uitwisseling van data versus uitwisseling van 3D </li></ul>

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