Matthias Trapp, Tassilo Glander, Henrik Buchholz, Jrgen Dllner - PowerPoint PPT Presentation
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Title: Matthias Trapp, Tassilo Glander, Henrik Buchholz, Jrgen Dllner
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3D Generalization Lensesfor Interactive Focus
Context Visualizationof Virtual City Models
- Matthias Trapp, Tassilo Glander, Henrik Buchholz,
Jürgen Döllner - Hasso-Plattner-Institut,
- University of Potsdam Germany
- 12th International ConferenceInformation
Visualization9-11 July 2008
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Motivation Virtual 3D City Models
- Properties
- Large number of objects
- High degree of visual detail
- Tool for communicate complex 3D geoinformation
- Numerous applications
- ? Can lead to perceptional and cognitive overload
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Motivation Generalized Virtual 3D City Models
Glander, ACMGIS 2007, ICA WS 2008
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Motivation Combined Generalization Levels
- Simple case
- Single arbitrarily shaped, non-convex volume
(lens shape) - Two Levels of Abstraction (LOA)
- Model Complexity lt 500 MB (Geometry Textures)
Context (LOA1)
3D Lens Shape
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Motivation Combined Generalization Levels
- Complex case
- 3 intersecting lens shapes (multiple foci)
- Three Levels of Abstraction
- Model Complexity gt 2GB
- Challenges
- Interactive manipulation of lens shapes
- Combined usage (intersection, nesting) of
multiple lenses - Enabling arbitrary lens shapes
- Handling spatial data complexity
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Outline
- Related Work
- Conceptual Overview
- Preprocessing Focus Context Mappings
- Real-Time Rendering
- Application Examples
- Future Work Conclusions
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Related Work
- Interactive 3D Focus Context Visualization with
Lenses - 3D Magic LensesViega et. al, UIST 1996
- A Solution for the Focus and Context Problem in
Geo-Virtual EnvironmentsRopinski et. al, DMGIS
2005 - Real-Time Volumetric Tests Using Layered Depth
ImagesTrapp and Döllner, Eurographics 2008 - Generalization
- 2D Building Simplification Aggregatione.g.,
Mayer, ISPRS 1998 - Single 3D Building Simplificatione.g., Kada,
ISPRS WS 2006 - 3D Cell-Based City Model GeneralizationGlander
and Döllner, ACMGIS 2007
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Our Approach Conceptual Overview
- Preprocessing Phase
- Create levels of abstraction (LOA) and
volumetric depth sprites (VDS) - Rendering Phase
- Create / modify focus context mapping FNC
map(VDS, LOA) - Real-time image synthesis render(FNC)
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Automatic Generalization of Virtual 3D City Models
- Input City Model CM
- Output Levels of Abstraction LOA
- Process
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Preprocessing of Lens Volumes
- Input Derived or modeled solid polygonal shapes
S - Output Volumetric Depth Sprites VDS
- Processing
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Mapping Generalization Levels to Lens Volumes
- Mapping for n lenses and generalization levels
- Mapping Properties
- Prioritized, hierarchical one-to-one mapping (i
priority) - Additional attributes (colors, lens positioning
scaling,) - Mapping can be changed at run-time
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Real-time Rendering of Focus Context Mapping
- Multi-pass rendering clipping against VDS
- First pass render context
- Successively one pass per LOA
- Start with lowest priority i n
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Applications Examples Usage Scenarios
- Scene Lens with intersecting foci of multiple
non-convex volumes
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Applications Examples Usage Scenarios
- Camera Lens with nested foci of the same convex
volume
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Limitations Future Work
- Current conceptual limitations
- Only one-to-one mapping possible
- Model complexity requires out-of-core rendering
- Clipping limitations
- Under-sampling / aliasing artifacts
- No capping of clipped areas
- Future Work
- Extend mapping mechanism one-to-many
- Compensate sampling artifacts
- Enable capping of clipped areas
- Use cases that exploit technical potential
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Conclusions
- Wrap-up
- Concept technique for combing different levels
of generalization - Two phase process preprocessing rendering
- Hierarchical focus content mapping
- Interactive multi-pass rendering
- Potential for future work
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Thank You
- Contact
- Matthias Trapp matthias.trapp_at_hpi.uni-potsdam.de
- Tassilo Glander
- tassilo.glander_at_hpi.uni-potsdam.de
- Henrik Buchholz
- henrik.buchholz_at_hpi.uni-potsdam.de
- Computer Graphics Systems Group Prof. Dr.
Jürgen Döllner www.hpi.uni-potsdam.de/3d - Researchgroup 3D-Geoinformation www.3dgi.de
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Main References
- Glander, Döllner, Cell-Based Generalization of 3D
Building Groups with Outlier Management, ACMGIS,
2007 - Kada 3D Building Generalization Based on
Half-Space Modeling, Proceedings of the ISPRS
Workshop on Multiple Representation and
Interoperability of Spatial Data, 2006 - Mayer Model-Generalization of Building Outlines
on Scale-Spaces and Scale-Space Events,
International Archives of Photogrammetry and
Remote Sensing, Vol. 33, 1998 - Trapp, Döllner, Real-Time Volumetric Tests Using
Layered Depth Images, Eurographics 2008
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