Authors:
Raquel Concheiro
1
;
Margarita Amor
1
;
Emilio J. Padrón
1
and
Michael Doggett
2
Affiliations:
1
Universidade da Coruña, Spain
;
2
Lund University, Sweden
Keyword(s):
NURBS, Real-time and Interactive Methods, Culling Techniques, Deformable Surfaces.
Related
Ontology
Subjects/Areas/Topics:
CAGD/CAD/CAM Systems
;
Computer Vision, Visualization and Computer Graphics
;
Geometry and Modeling
;
Surface Modeling
Abstract:
NURBS (Non-uniform rational B-splines) surfaces are the standard freeform representation in Computer-Aided Design (CAD) applications. Rendering NURBS surfaces accurately while they are interactively manipulated and deformed is a challenging task. In order to achieve it, the elimination from pipeline in early stages of back-facing surfaces or surface pieces is a key advantage. Furthermore, an effective interactive manipulation implies that all the culling computations should be performed for each frame, facing the possibility of fast changes in occlusion information. In this paper, different interactive culling strategies for NURBS surfaces are presented and analyzed. These culling techniques are based on the exploitation of the geometric properties presented in a NURBS surface, that allow easily to find bounds for it in screen space for each frame. Furthermore, the culling overhead for our proposals is small compared to the computational saving, outperforming a proposal without culli
ng. An implementation of these strategies using current GPUs is presented, achieving real-time and interactive rendering rates of complex parametric models.
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