Compressed 3D urban models for Internet-based e-planning

Transkript

1 Compressed 3D urban models for Inerne-based e-planning, Kaja Ewald Nex Generaion 3D Ciy Models, Seie 1 Overview - Inroducion: he VEPS projec - 3D urban models in public paricipaion - Sysem archiecure - Compressed 3D Ciy Models - Summary Seie 2

2 VEPS Virual Environmenal Planning Sysem - A Parnership co-financed hrough ERDF Inerreg IIIB Norh Wes Europe 12/ /2007 Seie 3 Universiy of Salford Mancheser Digial Developmen Agency Universiy of Wes of England Clemenine Media Sugar Universiy of Applied Sciences CSTB Environmen Agency for England and Wales (Lead Parner). Universiy of Freiburg Seie 4

3 Overall Objecives Share echnical compeencies beween NWE parners in he field of 3-dimensional visualisaion, ICT applicaions o promoe public consulaion, environmenal modelling, daa collecion and use for e- Planning in erriorial developmen in NWE. Develop a common archiecure and mehodology drawing on ransnaional experience and he knowledge of planning regulaions and susainabiliy merics in NWE, o enable ciizens o view and respond o planned changes via home PCs. Refine and implemen a es-bed sysem in a number of demonsraions in he NWE region, hereby increasing ransnaional experience. Evaluae and ieraively refine he mehodology and he sysem archiecure and applicable open sandards. Seie 5 Tes-bed Sugar Rosenseinvierel Seie 6

4 Disric Characerisics The Rosenseinvierel consiss of waseland railway areas buil-up areas and presenly is divided ino several areas wih differen urbanisic paerns and diverse land use. consiss of 170 ha, hereof 60 ha of developmen area Seie 7 New Srucure Plan (Firs price) Büro Pesch und Parner Seie 8

5 LASER Y Z INS Public paricipaion Hypohesis: An ineracive hree-dimensional (3D) virual realiy visualisaion allows he viewer o experience he highly complex informaion wihou he need for raining because hey can see and experience wha he visual impacs of he planned developmen will be and can see he environmenal impac in he associaed model. Seie 9 Sysem archiecure QS(Daa) GPS Z Y Spaial DB Daa model Query Web 3D Service CiyGML Region Reques Region Web- Server compressed CiyGML Inerne Compression Web - Clien Planning (CAD) Web - Clien Seie 10

6 Simplificaion 100K Triangles 20K Triangles 5K Triangles V. Coors, Feaure Preserving Simplificaion in Web-based 3D-GIS, SmarGraphics 2001 Seie 11 Compression - Compression Daa volume 3DS VRML expor 7.00 MB VRML opimizaion 3.90 MB Gzip-Compression 0.98 MB Mesh Compression 0.18 MB - Seie 12

7 3D Mesh Compression - Triangle mesh Geomery (coordinaes V) Conneciviy (riangles T) // mesh in VRML97 / MPEG4 BIFS IndexedFaceSe { // geomery coord Coordinae { poin [ 0 0 0, ] } // conneciviy coordindex [ 0,1,2, 1,...] } - Conneciviy dominaes sorage cos Conneciviy: 3*4 bye / T Geomery: 3*4 bye / V T = 2 V in large meshes Seie 13 Nework: compression - Mesh compression Topological surgery (Taubin and Rossignac 1998) MPEG 4 sandard for 3D daa ransmission Conneciviy: abou 2.2 bis per riangle (increases for smaller meshes) Geomery: 6 bis per coordinae (decreases wih essellaion&quanizaion) - Conneciviy compression Edgebreaker (Rossignac 1999) Guaraneed upper bound (2 bi / riangle) Seie 14

8 Delphi compression: Edgebreaker raversal? x? x? x C? L?? R Marked (visied) No marked x Las visied? Nex o be encoded To-do sack? S? x? x? E CLERS sequence: 50% C riangles C: 0, L: 100, E: 101, R: 110, S: 111 Guaraneed 2 bi / riangle Seie 15 Delphi compression Compress mesh conneciviy: - Use same mesh raversal as in Edgebreaker - Guess symbol of nex riangle - If guess is correc, send one bi - If no, recify he guessed symbol - Resul: Apollo sequence - The beer he guesses, he beer he bi rae V. Coors, J. Rossingnac: Delphi: geomery-based conneciviy predicion in riangle mesh compression The Visual CompuerVol. 20, Number 8-9, November 2004, pp Seie 16

9 Delphi compression Already covered area - g(c) = c.n.g + c.p.g - c.o.g Acive border B -, g(c) = min P, g(c) g(c) p B c.n - d =, g(c) E V l d c c.p V r c.o Seie 17 Delphi compression: guess conneciviy - d > τ E => guess C g(c) Guess C - d <= τ E = V r V l => guess R V r = V l => guess L V r V l => guess S = V r = V l => guess E g(c) Guess R g(c) g(c) Guess L g(c) Guess S Guess E Seie 18

10 Delphi compression: wrong guess Recify guess: - Wrong C can be L, E, R, or S - Wrong L can be C, R, or S - Wrong E has o be C g(c) - Wrong R can be C, L, or S - Wrong S can be C, L, R, or S Guess S in siuaion S bu is no ip Seie 19 Delphi compression: example Edgebreaker Delphi R R R f, R L C L E E S R C R f, R CLERS sequence: CRSRLECRRRLE (32 bi) Apollo sequence: ((), (f, R), (), (), (), (), (), (), (f, R), (), (), ()) (16 bi) Seie 20

11 Delphi Compression: cow model (2904 V, 5804 T) Edgebreaker: 2,26 bi per verex Delphi: 1,6 bi per verex Seie 21 Compressed Urban Models Darmsad Bell Tower Sugar downown (111 buildings) Sugar residenial (6771 buildings) Seie 22

12 Compression resuls (color per riangle) #componens Sugar downown 111 Sugar residenial 6771 Darmsad Bell Tower 372 #Triangles 5, ,306 92,188 Vrml file size 435 kb kb 2913 kb compressed 31 kb 1108 kb 199 kb Compression 309 ms 8078 ms 1700 ms Decompression 247 ms 6588 ms 1529 ms Seie 23 Implemened in Java / Java3D Seie 24

13 Applied 3D Mesh Compression o CiyGML CiyGML model Solid geom. Triangulae and build conneciviy Mesh compression geomery. Quanizaion n Predicion Arihmeic Coder CiyGML does no model conneciviy conneciviy Binary ML CLERS / Apollo seq. Compressed CiyGML Seie 25 Summary - Delphi 3D Mesh compression reduces 3D urban models up o 95% - Main componen is geomery (coordinaes) - Conneciviy cos almos zero - Bu conneciviy informaion is needed for efficien Delphi compression - Compression enables 3D models on mobile devices see: Seie 26

14 Vielen Dank für Ihre Aufmerksamkei Barks, Fuchs: CP 2, BL DD 11 Seie 27