A unified representation for freeform surfaces: NURBS-compatible subdivision surfaces

Decanato - Facoltà di scienze informatiche

Data d'inizio: 5 Febbraio 2010

Data di fine: 6 Febbraio 2010

The Faculty of Informatics is pleased to announce a seminar given by Tom Cashman

DATE: Friday, February 5th, 2010
PLACE: USI Università della Svizzera italiana, room SI-008, Informatics building (Via G. Buffi 13)
TIME: 14.00

Smooth surfaces that have a controllable shape (freeform surfaces) are used in automotive and aeronautical engineering, consumer product design, animated films, special effects, and even architecture and sculpture. To design these surfaces there are two main competing representations: NURBS, and subdivision surfaces. Both were created around thirty years ago and both are based on the theory of B-splines, but they extend B-splines in incompatible ways, and different industries have therefore established a preference for one representation over the other. NURBS are the dominant standard for engineering applications, while subdivision surfaces are very popular for use in films and computer games. However there are benefits of subdivision surfaces (arbitrary topology) which would be useful within engineering, and features of NURBS (arbitrary degree and non-uniform parametrisations) which would make good additions to current subdivision surfaces.

This talk describes my work for a PhD at the University of Cambridge, which offers a solution to this incompatibility divide. The work was presented at SIGGRAPH 2009, and develops a set of arbitrary topology subdivision surfaces which are NURBS-compatible: they are able to represent any existing NURBS patch. This is the first time that the complete set of NURBS has been freed from topological restrictions, and the first time that subdivision surfaces are able to benefit from the full set of NURBS features. I will describe the key ideas that makes these surfaces possible, and show our solutions to important questions surrounding the smoothness of the resulting surfaces.

Tom Cashman studied Mathematics and Computer Science at the University of Cambridge and graduated in 2006. Since then he has been a PhD student in the `Rainbow' research group (part of the Cambridge Computer Laboratory) under the supervision of Dr Neil Dodgson. His PhD research surrounds surfaces and their representations, and he has also collaborated with Microsoft Research in Cambridge on applications of subdivision surfaces in Computer Vision. Tom is due to start a postdoc working with Prof. Hormann at USI, in May 2010.

HOST: Prof. Kai Hormann