Slide1:
Interactive Multi-Perspective Views of Virtual 3D Landscape and City Models
Haik Lorenz, Matthias Trapp, Markus Jobst, Jürgen Döllner
Hasso-Plattner-Institute
Computer Graphics Systems Group
Prof. Dr. Jürgen Döllner
University Potsdam
www.hpi.uni-potsdam.de/3d
www.3dgi.de
Motivation: Why Multi-Perspective Views ?: Motivation: Why Multi-Perspective Views ? WRAP UP: Goals for 3D Visualization
Maintain advantages of 3D visualization
Offer navigation and orientation aid
Increase the effectiveness of available screen space
Reduce noise and dead values in the distance
Existing Solution: Detail + Overview Visualization: Existing Solution: Detail + Overview Visualization Detail Overview
Our Solution: Multi-Perspective Views: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 4 Our Solution: Multi-Perspective Views
Outline: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 5 Outline
Related Work
Concept
Implementation Sketch
Performance Results & Discussion
Future Work & Open Issues
Conclusions
Related Work: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 6 Related Work Art of H.C. Berann
Panorama Maps with Non-linear Ray-tracing [Falk ’07]
Detail-In-Context Visualization for Satellite Imaginary [Böttger, EG’08]
Concept – Effective Presentation of Spatial 3D Environments : 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 7 Concept – Effective Presentation of Spatial 3D Environments One concept: The Bendable Ground Plate
Two 3D visualization approaches:
Bird’s Eye View Deformation (Progressive Perspective)
“Which direction am I looking to?”
Pedestrian View Deformation (Degressive Perspective)
“Where am I going to?”
Concept – Bird’s eye View Deformation – Parameterization : 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 8 Concept – Bird’s eye View Deformation – Parameterization View-dependent parameters
C – camera position
β – viewing angle of the reference plane
bi – line separating focus and transition zone in the image
ri – line of the horizon in the image ri bi
Concept – Pedestrian’s View Deformation – Parameterization: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 9 Concept – Pedestrian’s View Deformation – Parameterization View-dependent parameters
C – camera position
β – angle between T and T’
db – distance between CT (C projected onto T ) and b
ds – width of the transition zone’s source area
Concept – … In Terms of Focus + Context Visualization: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 10 Concept – … In Terms of Focus + Context Visualization
Concept – Graphical Representations of Focus & Context Areas: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 11 Concept – Graphical Representations of Focus & Context Areas Cartographic design of the visualization:
Distinct rendering styles for focus and context areas
Transition zone: blending between focus and context
Vertex-based interpolation (style interpolator)
Implementation Sketch: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 12 Implementation Sketch Clue: Deformation before standard perspective projection
Global Deformation [Baar ’84]:
Per vertex, GPU based
Using vertex shader functionality
de Casteljau algorithm for Bézier spline:
Characteristics:
Single-pass rendering technique
Interactive, deformation recalculated per frame
No caching of deformed data necessary
Performance Results & Discussion (1): 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 13 Performance Results & Discussion (1) Test Data:
16,000 generically textured buildings, ~100 landmarks,
3 GB color aerial photo, 250 MB grayscale map,
Digital terrain model
Performance Results & Discussion (2): 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 14 Performance Results & Discussion (2) Performance Issues:
Main bottleneck = texture access
Cache efficiency is reduced dramatically
Additional data handling overhead for rendering 2 styles
Conclusion:
Using only adapted view frustum culling is not sufficient
Use hardware-based occlusion culling algorithms
Use distance-based geometric Level of Detail (LoD)
Future Work & Open Issues (1): Future Work & Open Issues (1) Improve User Interaction:
Transitions between bird’s eye and pedestrian view deformation
Adjust parameterization with respect to users speed or similar
Conduct user studies
Technical Enhancements:
Use dynamic mesh refinement for geometry [Lorenz, WSCG 08]
Add thematic information
Transfer Concept To:
Pedestrian View: Mobile Devices ?
Bird’s Eye View: Navigation Systems ?
Future Work & Open Issues (2): 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 16 Future Work & Open Issues (2) [Jobst, VISUAL 08, in review] Focus on cartographic aspects:
Minimize transition zone
Incorporate levels of detail/abstraction
Use non-photorealistic rendering (NPR)
[Glander, ACMGIS 2007]
Future Work & Open Issues (3): 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 17 Future Work & Open Issues (3) Silhouette enhancement via geometric scaling
Conclusions: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 18 Conclusions Features:
Interactive combination of two views
Seamlessly style interpolation
Increase effectiveness of representations
Extensible concept
Performance round-up:
Pedestrians View: minimal increase
Bird’s Eye View: heavy decrease
Possibilities for optimization
Future work:
Generalization of bendable plane concept
More styles for focus & context areas
Focus on: the user and more use cases
Slide19: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 19 Demo
Contact: 08.05.2007 Matthias Trapp, Hasso-Plattner-Institut, University Potsdam 20 Contact Thank You !
QUESTIONS ?
Matthias Trapp matthias.trapp@hpi.uni-potsdam.de
Computer Graphics Systems Group Prof. Dr. Jürgen Döllner www.hpi.uni-potsdam.de/3d
Researchgroup 3D-Geoinformation www.3dgi.de