Texture Mapping on Doo-Sabin Subdivision Surfaces Using Multiple Images
Zhiyong Huang2 and C hee Seng Neo1
2Department of Computer Science, School of Computing National University of Singapore, Singapore 117543
E-mail: [email protected]
05/01/22 Eurographics 2002 Short Presentation 2
Outline
1. Introduction 2. Our Work
3. Implementation and Results 4. Conclusion
5. Future Work
6. Acknowledgment
1. Introduction
• Subdivision: a process for defining a
smooth curve or surface as the limit of a sequence of successive refinements
– algorithms to generate new control points and polygons
05/01/22 Eurographics 2002 Short Presentation 4
• Advantages
– arbitrary topology
– scalability (level of detail) – numerical quality
– edit interface
• Disadvantages
– do not handle open surfaces well
– boundaries of an open surface shrink in each subdivision
Texture Mapping on Subdivision Surfaces
• DeRose et al. 1998
– texture mapping of Catmull-Clark
subdivision surfaces using only one image
• Piponi and Borshukov 2000
– seamless texture mapping by model pelting and texture blending
05/01/22 Eurographics 2002 Short Presentation 6
Work of DeRose et al.
• Idea: subdivision takes place in a 5- space consisting of (x, y, z, s, t)
coordinates
1. the texture coordinates(s, t) are assigned to the control vertices (x, y, z)
2. the texture coordinates(s, t) are
subdivided using the same rules for (x, y, z)
Work of Piponi and Borshukov
• Idea: providing parameterizations from regions of subdivision surfaces
1. finding a way to texture regions on the model
– in a fashion that is intuitive for artists to work with
2. joining together different regions in a completely seamless way
05/01/22 Eurographics 2002 Short Presentation 8
2. Our Work
• Texture mapping on Doo-Sabin
subdivision surfaces using multiple images
Original nth refinement
?
Why Doo-Sabin Subdivision Surfaces
• Reason: new faces of control meshes may fall into a region of multiple texture maps, e.g., (b) and (c)
(a) F-faces (b) E-faces (c) V-faces
05/01/22 Eurographics 2002 Short Presentation 10
Doo-Sabin Subdivision Surfaces
• Created by Donald Doo and Malcolm Sabin in 1978
– Based on quadratic uniform B-spline surfaces
– Produce C1 continuity
Overview of Our Method
• Idea: the further splitting
– the individual treatment of the F-faces, E- faces and V-faces. 7 cases to consider:
• F-face with (1) single map, (2) two maps, (3) multiple maps, E-face with (4) one map (5) two maps, V-face with (6) single map, (7) multiple maps
– for ease of description, a cube is used
05/01/22 Eurographics 2002 Short Presentation 12
F-faces
• For each n-sided face F in the original
polyhedron, linking the new vertices of F
forms a new n-sided face
The Treatment of the F-faces
1. A new F-face falls into a region of one texture map completely (easiest)
• directly apply the method DeRose et al.
05/01/22 Eurographics 2002 Short Presentation 14
2. A new F-face falls into a region of two texture maps
• split the F-face into two faces
• 4 texture coordinates from each image are calculated
• Ensure continuity between two textures
– Texture coordinate A, B, A’ and B’ will determine continuity
– Correct texture coordinate A, B, A’ and B’
05/01/22 Eurographics 2002 Short Presentation 16
3. A new F-face falls into a region of more than two texture maps
• split the new face into n multiple parts (details in the paper)
The Treatment of E-faces
• For each edge E common to two faces F and F’, a
new 4-sided face is made by linking the images of the end vertices of E on the faces F and F’
05/01/22 Eurographics 2002 Short Presentation 18
4. A new E-face falls into a region of one texture map
directly apply the method DeRose et al.
5. A new E-face falls into a region of two texture maps
05/01/22 Eurographics 2002 Short Presentation 20
The Treatment of V-faces
• For each n-spoked (n>2) vertex V, where n faces meet, a new n-sided face is formed by linking the new vertices formed by V on the faces meeting at V
6. A new V-face falls into a region of one texture map
• directly apply the method DeRose et al.
05/01/22 Eurographics 2002 Short Presentation 22
7. A new V-face falls into a region of multiple texture maps (details in the paper)
3. Implementation and Results
• Intel Pentium III PC
• MS Window NT 4.0 & Visual C++ 6.0
• OpenGL Library Packages
05/01/22 Eurographics 2002 Short Presentation 24
• Demo
4. Conclusion
• A texture mapping method to generalize the method of DeRose et al.
– use multiple images
– maintain smoothness of texture between any adjacent faces mapped by different images
05/01/22 Eurographics 2002 Short Presentation 26
5. Future Work
• Reduce time complexity
• 3D morphing
– texture mapped subdivision surfaces
