Discrete B-splines and subdivision techniques in computer-aided geometric design and computer graphics

1980 ◽  
Vol 14 (2) ◽  
pp. 87-111 ◽  
Author(s):  
Elaine Cohen ◽  
Tom Lyche ◽  
Richard Riesenfeld
2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Soroosh Tayebi Arasteh ◽  
Adam Kalisz

AbstractSplines are one of the main methods of mathematically representing complicated shapes, which have become the primary technique in the fields of Computer Graphics (CG) and Computer-Aided Geometric Design (CAGD) for modeling complex surfaces. Among all, Bézier and Catmull–Rom splines are the most common in the sub-fields of engineering. In this paper, we focus on conversion between cubic Bézier and Catmull–Rom curve segments, rather than going through their properties. By deriving the conversion equations, we aim at converting the original set of the control points of either of the Catmull–Rom or Bézier cubic curves to a new set of control points, which corresponds to approximately the same shape as the original curve, when considered as the set of the control points of the other curve. Due to providing simple linear transformations of control points, the method is very simple, efficient, and easy to implement, which is further validated in this paper using some numerical and visual examples.


2020 ◽  
Vol 8 (2) ◽  
pp. 39-50
Author(s):  
Azhar Ahmad

Makalah ini membincangkan satu kaedah pembinaan lengkungan peralihan berbentuk C yang memenuhi syarat-syarat data interpolasi Hermite Lengkungan peralihan ini dibina berasaskan gabungan dua pilin kuadratik nisbah Bezier atau gabungan bersama satu segmen garis lurus bagi mencapai keselanjaran pada keseluruhan binaan. Kaedah analisis geometri bersama syarat kemonotonan suatu lengkungan kuadratik nisbah Bezier telah digunakan bagi mencapai objektif kajian. Hasil kajian yang dicapai adalah satu teknik pembinaan yang membolehkan kita memperolehi lengkungan peralihan secara terus, mudah diaplikasikan serta tanpa perlu menggunakan sebarang prosedur tranformasi affin. Syarat untuk lengkungan peralihan ini terhasil ditentukan oleh data Hermite yang diberi dan kepelbagaiannya pula dikawal oleh panjang segmen garis lurus yang menghubungkan kedua-dua pilin berkenaan. Keupayaan memenuhi sifat-sifat interpolasi ini memberi banyak kelebihan dan amat sesuai untuk aplikasi tertentu di dalam CAGD (Computer Aided Geometric Design), umpamanya rekabentuk produk industri, trajektori robot non-holonomic, serta rekabentuk mendatar landasan keretapi dan lebuhraya. Oleh kerana kuadratik nisbah Bezier merupakan sebahagian daripada perwakilan NURBS (Nonuniform Rational B-splines) maka adalah mudah bagi kita mengabungjalinkan formulasi lengkungan peralihan yang dicadangkan ini ke dalam kebanyakan sistem pengaturcara CAD (Computer Aided Design).


Author(s):  
Q. J. Ge ◽  
D. Kang ◽  
M. Sirchia

Abstract This paper takes advantage of the duality between point and plane geometries and studies a class of tensor-product surfaces that can be generated kinematically as surfaces enveloped by a plane under two-parameter rational Bézier motions. The results of this cross-disciplinary work, between the field of Computer Aided Geometric Design and Kinematics, can be used as a basis for studying geometric and kinematic issues associated with the design and manufacture of freeform surfaces.


1999 ◽  
Vol 121 (4) ◽  
pp. 502-506 ◽  
Author(s):  
Q. J. Ge ◽  
M. Sirchia

This paper brings together the notion of analytically defined two-parameter motion in Theoretical Kinematics and the notion of freeform surfaces in Computer Aided Geometric Design (CAGD) to develop methods for computer aided design of two-parameter freeform motions. In particular, a rational Be´zier representation for two-parameter freeform motions is developed. It has been shown that the trajectory surface of such a motion is a tensor-product rational Be´zier surface and that such a kinematically generated surface has a geometric as well as a kinematic control structure. The results have not only theoretical interest in CAGD and kinematics but also applications in CAD/CAM and Robotics.


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