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 Introduction Related work Related work User interface User interface Algorithm Algorithm Results Results Conclusions and future work Conclusions and future work

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

5. Introduction (2/3) Our goal is to develop an interactive designing and browsing system. Our goal is to develop an interactive designing and browsing system. Cannot see all of the 3D volumetric information simultaneously. Cannot see all of the 3D volumetric information simultaneously. Can see only one 2D cross-section at a time.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.Providing guiding information.

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

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

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

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

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

12. User interface The system comprised two functions: browsing and modeling. The system comprised two functions: browsing and modeling. Browsing interface: Browsing interface: The browsing interface is a subset of the modeling interface.The browsing interface is a subset of the modeling interface. A standard 3D model viewerA standard 3D model viewer Inspection of internal texture using a cut operation. Inspection of internal texture using a cut operation. Rotating and translating the model. Rotating and translating the model. The user can cut the model by drawing a freedom stroke that crosses the model on the screen. 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: The modeling process has the following steps: 1.Cut the target 3D model and specify a 3D region to be textured by clicking on the cross-section. 2.Choose one of the three texture types to use for the region. 3.Import a reference 2D image. 4.Establish the correspondence between the 2D reference image and the cross-section of the 3D model by providing the necessary guidance information. 5.Repeat steps 1-4 for each 3D region.

15. Modeling interface

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

17. Isotropic textures

18. Layered textures

20. Oriented textures

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

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

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

24. Thin plate Interpolation Thin plate Interpolation Thin plate Interpolation Like taking a thin sheet of metal, laying it horizontally so that it touches the tips of a collection of vertical poles at the positions and heights given by the constraints of the problem Like taking a thin sheet of metal, laying it horizontally so that it touches the tips of a collection of vertical poles at the positions and heights given by the constraints of the problem The sheet resists the bending and smoothly changes its height in the positions between the poles The sheet resists the bending and smoothly changes its height in the positions between the poles The springy resistance is mimicked by the energy functional The springy resistance is mimicked by the energy functional Solution to such constrained problems draws from the branch of mathematics called Variational CalculusSolution to such constrained problems draws from the branch of mathematics called Variational Calculus Hence these techniques are called Variational methodsHence these techniques are called Variational methods

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

28. Algorithm Oriented textures: 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 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.The system computes the color for each pixel in the cross-section.

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

31. Results

32. Results

33. Results

34. Results

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

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