Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

3D Generalization Lenses (IV 2008)

817 views

Published on

Published in: Technology
  • Be the first to comment

  • Be the first to like this

3D Generalization Lenses (IV 2008)

  1. 1. Matthias Trapp , Tassilo Glander, Henrik Buchholz, Jürgen Döllner Hasso-Plattner-Institut, University of Potsdam Germany 12 th International Conference Information Visualization 9-11 July 2008 3D Generalization Lenses for Interactive Focus + Context Visualization of Virtual City Models
  2. 2. Motivation – Virtual 3D City Models <ul><li>Properties: </li></ul><ul><ul><li>Large number of objects </li></ul></ul><ul><ul><li>High degree of visual detail </li></ul></ul><ul><ul><li>Tool for communicate complex 3D geoinformation </li></ul></ul><ul><ul><li>Numerous applications </li></ul></ul><ul><ul><li> Can lead to perceptional and cognitive overload </li></ul></ul>
  3. 3. Motivation – Generalized Virtual 3D City Models [Glander, ACMGIS 2007, ICA WS 2008]
  4. 4. Motivation – Combined Generalization Levels <ul><ul><li>Simple case: </li></ul></ul><ul><ul><li>Single arbitrarily shaped, non-convex volume (lens shape) </li></ul></ul><ul><ul><li>Two Levels of Abstraction (LOA) </li></ul></ul><ul><ul><li>Model Complexity < 500 MB (Geometry + Textures) </li></ul></ul>Context (LOA 1 ) 3D Lens Shape Single Focus (LOA 0 )
  5. 5. Motivation – Combined Generalization Levels <ul><ul><li>Comlex case: </li></ul></ul><ul><ul><li>3 intersecting lens shapes (multiple foci) </li></ul></ul><ul><ul><li>Three Levels of Abstraction </li></ul></ul><ul><ul><li>Model Complexity > 2GB </li></ul></ul>
  6. 6. Outline <ul><li>Related Work </li></ul><ul><li>Conceptual Overview </li></ul><ul><li>Preprocessing & Focus + Context Mappings </li></ul><ul><li>Real-Time Rendering </li></ul><ul><li>Application Examples </li></ul><ul><li>Future Work & Conclusions </li></ul>
  7. 7. Related Work <ul><li>Interactive 3D Focus + Context Visualization with Lenses </li></ul><ul><ul><li>3D Magic Lenses Viega et. al, UIST 1996 </li></ul></ul><ul><ul><li>A Solution for the Focus and Context Problem in Geo-Virtual Environments Ropinski et. al, DMGIS 2005 </li></ul></ul><ul><ul><li>Real-Time Volumetric Tests Using Layered Depth Images Trapp and Döllner, Eurographics 2008 </li></ul></ul><ul><li>Generalization </li></ul><ul><ul><li>2D Building Simplification & Aggregation e.g., Mayer, ISPRS 1998 </li></ul></ul><ul><ul><li>Single 3D Building Simplification e.g., Kada, ISPRS WS 2006 </li></ul></ul><ul><ul><li>3D Cell-Based City Model Generalization Glander and Döllner, ACMGIS 2007 </li></ul></ul>
  8. 8. Our Approach: Conceptual Overview <ul><li>Preprocessing Phase: </li></ul><ul><ul><li>Create levels of abstraction ( LOA ) and volumetric depth sprites ( VDS ) </li></ul></ul><ul><li>Rendering Phase: </li></ul><ul><ul><li>Create / modify focus + context mapping: FNC = map( VDS , LOA ) </li></ul></ul><ul><ul><li>Real-time image synthesis: render(FNC) </li></ul></ul>
  9. 9. Automatic Generalization of Virtual 3D City Models <ul><li>Input: City Model CM </li></ul><ul><li>Output: Levels of Abstraction LOA </li></ul><ul><li>Process: </li></ul>
  10. 10. Preprocessing of Lens Volumes <ul><li>Input: Derived or modeled solid polygonal shapes: S </li></ul><ul><li>Output: Volumetric Depth Sprites VDS </li></ul><ul><li>Processing: </li></ul>
  11. 11. Mapping Generalization Levels to Lens Volumes <ul><li>Mapping for n lenses and generalization levels: </li></ul><ul><li>Mapping Properties: </li></ul><ul><ul><li>Prioritized, hierarchical one-to-one mapping ( i = priority) </li></ul></ul><ul><ul><li>Additional attributes (colors, lens positioning & scaling,…) </li></ul></ul><ul><ul><li>Mapping can be changed at run-time </li></ul></ul>
  12. 12. Real-time Rendering of Focus + Context Mapping <ul><li>Multi-pass rendering + clipping against VDS: </li></ul><ul><ul><li>First pass: render context </li></ul></ul><ul><ul><li>Successively: one pass per LOA </li></ul></ul><ul><ul><li>Start with lowest priority: i = n </li></ul></ul>
  13. 13. Applications Examples & Usage Scenarios <ul><li>Scene Lens with intersecting foci of multiple non-convex volumes </li></ul>
  14. 14. Applications Examples & Usage Scenarios <ul><li>Camera Lens with nested foci of the same convex volume </li></ul>
  15. 15. Limitations & Future Work <ul><li>Current conceptual limitations: </li></ul><ul><ul><li>Only one-to-one mapping possible </li></ul></ul><ul><ul><li>Model complexity requires out-of-core rendering </li></ul></ul><ul><li>Clipping limitations: </li></ul><ul><ul><li>Under-sampling / aliasing artifacts </li></ul></ul><ul><ul><li>No capping of clipped areas </li></ul></ul><ul><li>Future Work: </li></ul><ul><ul><li>Extend mapping mechanism: one-to-many </li></ul></ul><ul><ul><li>Compensate sampling artifacts </li></ul></ul><ul><ul><li>Enable capping of clipped areas </li></ul></ul><ul><ul><li>Use cases that exploit technical potential </li></ul></ul>
  16. 16. Conclusions <ul><li>Wrap-up: </li></ul><ul><ul><li>Concept + technique for combing different levels of generalization </li></ul></ul><ul><ul><li>Two phase process: preprocessing + rendering </li></ul></ul><ul><ul><li>Hierarchical focus + content mapping </li></ul></ul><ul><ul><li>Interactive multi-pass rendering </li></ul></ul><ul><ul><li>Potential for future work </li></ul></ul>
  17. 17. Thank You… <ul><li>Contact: </li></ul><ul><li>Matthias Trapp [email_address] </li></ul><ul><li>Tassilo Glander </li></ul><ul><li>[email_address] </li></ul><ul><li>Henrik Buchholz </li></ul><ul><li>[email_address] </li></ul><ul><li>Computer Graphics Systems Group Prof. Dr. Jürgen Döllner www.hpi.uni-potsdam.de/3d </li></ul><ul><li>Researchgroup 3D-Geoinformation www.3dgi.de </li></ul>
  18. 18. Main References <ul><li>Glander, Döllner, Cell-Based Generalization of 3D Building Groups with Outlier Management , ACMGIS, 2007 </li></ul><ul><li>Kada: 3D Building Generalization Based on Half-Space Modeling , Proceedings of the ISPRS Workshop on Multiple Representation and Interoperability of Spatial Data, 2006 </li></ul><ul><li>Mayer: Model-Generalization of Building Outlines on Scale-Spaces and Scale-Space Events , International Archives of Photogrammetry and Remote Sensing, Vol. 33, 1998 </li></ul><ul><li>Trapp, Döllner, Real-Time Volumetric Tests Using Layered Depth Images, Eurographics 2008 </li></ul>

×