Volumetric Illustration: Designing 3D Models with Internal Textures

1. Volumetric Illustration: Designing 3D Models with Internal Textures Shigeru Owada Frank Nielsen Makoto Okabe Takeo Igarashi The University of Tokyo Sony CS Laboratories Inc. SIGGRAPH 2004

2. Abstract

3. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

4. Introduction (1/3) • The application of a surface representation is limited because it lacks internal information. • Volumetric representations have complementary advantages and limitations. • Modeling is especially problematic. • The main source of volume data are the capture of real-world objects and procedural design. • Not appropriate for drawing quickly for communication purpose.

5. Introduction (2/3) • Our goal is to develop an interactive designing and browsing system. • Cannot see all of the 3D volumetric information simultaneously. • Can see only one 2D cross-section at a time. • System synthesizes the internal textures for a cross-section by using 2D reference images instead of maintaining all the 3D volumetric data • Providing guiding information.

6. Introduction (3/3) • Technical contributions: • Interface used to assign internal textures to a given surface mesh. • Algorithms that synthesize texture on a cross-section. • Allowing non-experts to create volumetirc illustrations rapidly.

8. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

9. Related work(1/2) • Volumetric modeling: • [Perlin 1985; Kniss et al. 2002] Using procedural methods which enable the user to design various 3D structure. • [Banvard 2002] Using special-purpose instruments to get the volumetric data. • Texture synthesis: • [Heeger and Bergen 1995] frequency domain. • [Efros and Leung 1999; Wei and Levoy 2000] pixel-based. • [Efros and Freeman 2001; Kwatra et al. 2003] patch-based. • [Stam 1997;Cohen et al. 2003] non-periodic tiling.

10. Related work(2/2) • Non-photorealistic modeling and rendering: • [Lake et al. 2000; Kalnins et al. 2002]the stylized rendering of 3D models that synthesize interesting 2D pictures by adding details to simple 3D geometries on the fly • Our system provides a tailored user interface for intuitively designing volumetric illustrations.

11. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

12. User interface • The system comprised two functions: browsing and modeling. • Browsing interface: • The browsing interface is a subset of the modeling interface. • A standard 3D model viewer • Inspection of internal texture using a cut operation. • Rotating and translating the model. • The user can cut the model by drawing a freedom stroke that crosses the model on the screen.

14. Modeling interface • The modeling process has the following steps: • Cut the target 3D model and specify a 3D region to be textured by clicking on the cross-section. • Choose one of the three texture types to use for the region. • Import a reference 2D image. • Establish the correspondence between the 2D reference image and the cross-section of the 3D model by providing the necessary guidance information. • Repeat steps 1-4 for each 3D region.

15. Modeling interface

16. Modeling interface • The current system supports three types of texture: isotropic, layered, and oriented

17. Isotropic textures

18. Layered textures

19. Layered textures

20. Oriented textures

21. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

22. Algorithms • Using the curved plane made by cut operation , a model is divided by CSG operation [Hoffman 1989]. • Isotropic textures: • No dependency on position or direction. • Simply using a standard 2D texture-synthesis algorithm. [Wei and Levoy 2000; Cohen et al. 2003; Kwatra et al. 2003]

23. Algorithm • Layered textures: • The system generates a reference control map for the reference image and a target control map for the cross-section. • A control map is grayscale 2D image • The grayscale value represent a smooth 2D depth field. • Upper bound 0, lower bound 1. • Using a thin-plate interpolation technique to compute the smooth depth field.

25. Algorithm • Using a pixel-based technique which similar to field distortion synthesis to start texture synthesis process. • But have some difference.

27. Algorithm • Oriented textures: • The synthesis process for an oriented texture requires a 3D reference volume and a flow field defined in the 3D region in the surface mesh. • The system computes the color for each pixel in the cross-section.

29. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

30. Results

31. Results

32. Results

33. Results

34. Outline • Introduction • Related work • User interface • Algorithm • Results • Conclusions and future work

35. Conclusion and future work • A modeling and browsing system that adds internal textures to a surface mesh. • This system will be useful for conveying volumetric information. • In future work , improve the performance and quality of the overall process.