1. NPar 20081 Non-linear Perspective Widgets for Creating Multiple-View Images Nisha Sudarsanam (Mindjet Corp) Cindy Grimm (Washington Univ. in St. Louis) Karan Singh (University of Toronto)

2. NPar 20082 What is non-linear perspective? Npar 20082 Pearblossom Hwy. No. 2 (D.Hockney 1986) © 1986, D. Hockney, The J. Paul Getty Museum, Los Angeles. Picasso’s Guitar, Glass and Fruit Dish

3. NPar 20083 Composition of linear perspective views Npar 20083 Initial Scene View 1 View 2 View 3 Final Scene

4. NPar 20084 Motivation Linear perspective is sometimes restrictive Npar 20084

5. NPar 20085 Combine to make one view Npar 20085 Unwrap widget Fish-eye Unwrap plus a fish-eye

6. NPar 20086 User interface problem What do you want to see where? Npar 20086

7. NPar 20087 Our contribution Task breakdown for user – 3D selection of model subset – Desired viewing attributes – 2D placement in image Underlying framework for widget creation – Specify region of interest and fall-off – Support specific viewing effects – Automatic 2D placement algorithms Npar 20087

8. NPar 20088 Previous work View transform as space deformation – “Bend” view rays in space J. Brosz, F. Samavati, S. Carpendale, M. Sousa, “Single camera flexible projection”, Npar 2007 V. Popescu, C. Mei, J. Dauble, E. Sacks, “An efficient error-bounded general camera model”, DPVT 2006 – Modify perspective view to curve space Npar 20088

9. NPar 20089 Previous work Manual placement of cameras – Blend to get camera for each point in space Karan Singh, “A fresh perspective”, GI 2002 P. Coleman, K. Singh, L. Barrett, N. Sudarsanam, C. Grimm, “3D screen-space widgets for non-linear projection”, Graphite 2005 – Our rendering approach – Very flexible, user-intensive Npar 20089

10. NPar 200810 Key differences Local deformation specified wrt global camera – Can change global camera Npar 200810

11. NPar 200811 Key differences Use interactive widgets – Specifies a specific view transformation – Encapsulates input parameters – Can string widgets together Npar 200811

12. NPar 200812 Unwrap widget 3D volume, view direction – Look down vector – Placed on side of screen (default) Surface Normal Npar 200812

13. NPar 200813 Unwrap widget Keeps view direction as camera changes – May move on screen Surface Normal Npar 200813

14. NPar 200814 Fisheye widget Magnify selected region m = 1.19 m = 1.45 m = 1.6 Npar 200814

15. NPar 200815 Clip widget Select area – Pulls to side Npar 200815 Destination area Rotating the camera

16. NPar 200816 Clip widget Npar 200816

17. NPar 200817 Panorama widget Input is key frames Npar 200817

18. NPar 200818 Chaining and multiple widgets Npar 200818

19. NPar 200819 Framework 3D region of influence – Fall-off Changes to the camera Destination area – Relative to bbox – COP Destination size – Bbox of region E.g., box (clip) E.g., Zoom (fisheye) E.g., To side (unwrap) Same or smaller (most) Npar 200819

20. NPar 200820 System help Automatic routines for determining best destination location, size – Implemented as a Center of Projection change – Based on projection of bounding boxes Automatic weight fall offs – Multiple widgets: average effect based on weights Npar 200820

21. NPar 200821 Rendering GPU implementation Calculate camera for each vertex – Based on 3D influences, local camera changes – Average projection from each camera Use original camera for lighting Npar 200821

22. NPar 200822 Conclusion Encapsulate specific changes in widgets Framework for making and combining the widgets Easy to use, but not as flexible Npar 200822