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Necessary conditions for subdivision surfaces (1997)

by H Prautzsch, U Reif
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Subdivision for Modeling and Animation

by Denis Zorin, Peter Schr öder, Tony DeRose, Jos Stam, Joe Warren, Henrik Weimer - SIGGRAPH ’99 Courses, no. 37. ACM SIGGRAPH , 1999
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Abstract - Cited by 214 (24 self) - Add to MetaCart
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Analysis of Algorithms Generalizing B-Spline Subdivision

by Jörg Peters, Ulrich Reif - SIAM J. Numer. Anal , 1997
"... A new set of tools for verifying smoothness of surfaces generated by stationary subdivision algorithms is presented. The main challenge here is the verification of injectivity of the characteristic map. The tools are sufficiently versatile and easy to wield to allow, as an application, a full analys ..."
Abstract - Cited by 50 (2 self) - Add to MetaCart
A new set of tools for verifying smoothness of surfaces generated by stationary subdivision algorithms is presented. The main challenge here is the verification of injectivity of the characteristic map. The tools are sufficiently versatile and easy to wield to allow, as an application, a full analysis of algorithms generalizing biquadratic and bicubic B-spline subdivision. In the case of generalized biquadratic subdivision the analysis yields a hitherto unknown sharp bound strictly less than one on the second largest eigenvalue of any smoothly converging subdivision. Keywords: subdivision, arbitrary topology, characteristic map, Doo-Sabin Algorithm, CatmullClark algorithm, B-spline AMS subject classification: 65D17, 65D07, 68U07 Abbreviated title: Generalized B-Spline Subdivision 1 Introduction The idea of generating smooth free-form surfaces of arbitrary topology by iterated mesh refinement dates back to 1978, when two papers [CC78], [DS78] appeared back to back in the same issue ...
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...ce y is a regular C 1 -manifold for almost every choice of initial data B 0 . A proof of this theorem can be found in [Rei95a]. Generalizations, though not required here, are provided in [Rei95b] and =-=[PR97]-=-. Subsequently, it will be assumed that the eigenvalues of A satisfy the assumptions of Theorem 2.1, andswill be referred to as the subdominant eigenvalue. The following theorem states a necessary con...

Improved Triangular Subdivision Schemes

by Hartmut Prautzsch, Georg Umlauf , 1998
"... In this article we improve the butterfly and Loop's algorithm. As a result we obtain subdivision algorithms for triangular nets which can be used to generate G 1 - and G 2 - surfaces, respectively. Keywords: Subdivision, interpolatory subdivision, Loop's algorithm, butterfly algorithm ..."
Abstract - Cited by 24 (8 self) - Add to MetaCart
In this article we improve the butterfly and Loop's algorithm. As a result we obtain subdivision algorithms for triangular nets which can be used to generate G 1 - and G 2 - surfaces, respectively. Keywords: Subdivision, interpolatory subdivision, Loop's algorithm, butterfly algorithm. 1. Introduction Subdivision algorithms are popular in CAGD since they provide simple, efficient tools to generate arbitrary free form surfaces. For example, the algorithms by Catmull and Clark [3] and Loop [7] are generalizations of well-known spline subdivision schemes. Therefore the surfaces produced by these algorithms are piecewise polynomial and at ordinary points curvature continuous. At extraordinary points however, the curvature is zero or infinite. In general, singularities at extraordinary points is an inherent phenomenon of subdivision, see [13, 12, 9]. The smoothness of a subdivision surface at its extraordinary points depends on the spectral properties of the associated subdivision mat...

Smoothness of stationary subdivision on irregular meshes

by Denis Zorin - Constructive Approximation , 1998
"... We derive necessary and sufficient conditions for tangent plane and C k-continuity of stationary subdivision schemes near extraordinary vertices. Our criteria generalize most previously known conditions. We introduce a new approach to analysis of subdivision surfaces based on the idea of the univers ..."
Abstract - Cited by 24 (1 self) - Add to MetaCart
We derive necessary and sufficient conditions for tangent plane and C k-continuity of stationary subdivision schemes near extraordinary vertices. Our criteria generalize most previously known conditions. We introduce a new approach to analysis of subdivision surfaces based on the idea of the universal surface. Any subdivision surface can be locally represented as a projection of the universal surface, which is uniquely defined by the subdivision scheme. This approach provides us with a more intuitive geometric understanding of subdivision near extraordinary vertices. AMS MOS classification: 65D10, 65D17, 68U05
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...ch and Umlauf [21]; however, such schemes generate surfaces that are flat at extraordinary vertices (have zero curvature). At the same time degree bounds were derived for piecewisepolynomial schemes (=-=[23, 20]-=-), which indicate that schemes that generate non-flat surfaces of higher-order continuity are likely to have large supports. Still, construction of such schemes is of some interest. Another important ...

Triangle mesh subdivision with bounded curvature and the convex hull property

by Charles Loop
"... The masks for Loop’s triangle subdivision surface algorithm are modified resulting in surfaces with bounded curvature and the con-vex hull property. New edge masks are generated by a cubic polyno-mial mask equation whose Chebyshev coefficients are closely related to the eigenvalues of the correspond ..."
Abstract - Cited by 6 (0 self) - Add to MetaCart
The masks for Loop’s triangle subdivision surface algorithm are modified resulting in surfaces with bounded curvature and the con-vex hull property. New edge masks are generated by a cubic polyno-mial mask equation whose Chebyshev coefficients are closely related to the eigenvalues of the corresponding subdivision matrix. The mask equation is found to satisfy a set of smoothness constraints on these eigenvalues. We observe that controlling the root structure of the mask equation is important for deriving subdivision masks with non-negative weights.
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... smoothness properties are studied in terms of Taylor expansions over this plane. Necessary conditions for Gk continuity, for certain classes of subdivision surfaces, have been given by Prautzsch&Reif=-=[9]-=-. For curvature (G2) continuity, in addition to G1 continuity, the following must also hold: • A has a subsubdominant eigenvalue µ, where |µ| = λ2. • If Av = µv, then the surface defined by v ∈ span(x...

Subdivision Surfaces - Can they be Useful for Geometric Modeling Applications?

by Dan Gonsor, Marian Neamtu , 2001
"... This report summarizes the findings and recommendations of the authors concerning the usefulness of subdivision surfaces for geometric modeling, and in particular for engineering applications. The work described is a result of a three-month collaboration of the authors during the visit of the sec ..."
Abstract - Cited by 5 (0 self) - Add to MetaCart
This report summarizes the findings and recommendations of the authors concerning the usefulness of subdivision surfaces for geometric modeling, and in particular for engineering applications. The work described is a result of a three-month collaboration of the authors during the visit of the second author to Boeing in the Summer of 2001.

Convex triangular subdivision surfaces with bounded curvature

by Charles Loop , 2000
"... The edge masks for Loop’s triangular subdivision surface algorithm are modified resulting in surfaces with bounded curvature and the convex hull property. The new edge masks are derived from a polynomial mask equation whose Chebyshev expansion coefficients are closely related to the eigenvalues of t ..."
Abstract - Cited by 2 (0 self) - Add to MetaCart
The edge masks for Loop’s triangular subdivision surface algorithm are modified resulting in surfaces with bounded curvature and the convex hull property. The new edge masks are derived from a polynomial mask equation whose Chebyshev expansion coefficients are closely related to the eigenvalues of the corresponding subdivision matrix. The mask equation is found to satisfy a set of smoothness constraints on these eigenvalues. 1
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...onds to the extraordinary vertex. Higher order smoothness properties are studied in terms of Taylor expansions over this plane. Necessary conditions for Gk continuity have been given by Prautzsch&Reif=-=[7]-=-. For curvature continuity (G2), in addition to G1 continuity, the following must also hold: • A has a subsubdominant eigenvalue µ, where |µ| = λ2. • If Av = µv, then the surface defined by v ∈ span(x...

Fast evaluation of the improved loop’s subdivision surfaces

by Qing Pan, Guoliang Xu - Proc. of the Geometric Modeling and Processing 2004. Beijing: IEEE Computer Society , 2004
"... For obtaining better curvature distributions of subdivi-sion surfaces, various improvements for Loop’s subdi-vision scheme on triangular surface meshes have been made. A careful analysis shows that the fast evaluation technique of the subdivision surface proposed by Stam is no longer usable to these ..."
Abstract - Cited by 1 (0 self) - Add to MetaCart
For obtaining better curvature distributions of subdivi-sion surfaces, various improvements for Loop’s subdi-vision scheme on triangular surface meshes have been made. A careful analysis shows that the fast evaluation technique of the subdivision surface proposed by Stam is no longer usable to these improved schemes. This pa-per describes a fast evaluating algorithm for improved Loop’s subdivision surfaces. The algorithm is applica-ble to a vast class of subdivision schemes for triangular surface meshes. Using the proposed algorithm, one can evaluate the subdivision surface at any domain point for any set of input subdivision masks and a control mesh.
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...ce is G1 continuous. The smoothness of subdivision surfaces at points corresponding to extraordinary vertices is associated with the spectral properties of their subdivision matrices. We can refer to =-=[10, 11, 12, 15, 19, 20]-=- for the detail analysis. ∗Supported in part by NSFC grants 10241004, 10371130, National Innovation Fund 1770900, Chinese Academy of Sciences. Based on the spectral properties, Prautzsch and Umlauf in...

MASS: MULTIRESOLUTIONAL ADAPTIVE SOLID SUBDIVISION

by Yu-sung Chang , 2003
"... In this survey paper, we discuss subdivision geometry, subdivision schemes, its analysis and applications, especially from the view of solid modeling. Subdivision technique has been widely accepted in computer graphics and geometric design applications. However, it has been largely ignored in solid ..."
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In this survey paper, we discuss subdivision geometry, subdivision schemes, its analysis and applications, especially from the view of solid modeling. Subdivision technique has been widely accepted in computer graphics and geometric design applications. However, it has been largely ignored in solid modeling. The first few sections are devoted to the history of subdivision modeling and the review of existing subdivision schemes in detail. We also briefly review other solid modeling techniques. Next, we discuss the current mathematical technique to analyze subdivision schemes on both regular and extraordinary topologies. We provide examples of analysis on the schemes in prior sections. We discuss problems involving solid scheme analysis and suggest possible solutions. In addition, we review prior work using subdivision technique in various applications. The latter part of the paper devote to our novel subdivision solid schemes, ongoing research topics, and new ideas. We demonstrate the potential of subdivision solids by a variety of examples. Attractive features of subdivision solids are compared and addressed. We conclude the paper with the summary and the expectation for future of subdivision technique in solid modeling.

Lecturers

by Organizers Denis Zorin, Peter Schröder Caltech, Denis Zorin, Tony Derose, Adi Levin, Peter Schröder, Leif Kobbelt, Im Stadtwald, Wim Sweldens, Peter Schröder, Denis Zorin, Denis Zorin, Adi Levin, Leif Kobbelt, Wim Sweldens
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...d by 45 degrees. Problems with Curvature Continuity. While it is possible to obtain subdivision schemes which are C2-continuous, there are indications that such schemes either have very large support =-=[24, 21]-=-, or necessarily have zero curvature at extraordinary vertices. A compromise solution was recently proposed by Umlauf [22]. Nevertheless, this limitation is quite fundamental: degeneracy or discontinu...

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