| 词条 | Free-form deformation |
| 释义 |
In computer graphics, free-form deformation (FFD) is a geometric technique used to model simple deformations of rigid objects. It is based on the idea of enclosing an object within a cube or another hull object, and transforming the object within the hull as the hull is deformed. Deformation of the hull is based on the concept of so-called hyper-patches, which are three-dimensional analogs of parametric curves such as Bézier curves, B-splines, or NURBs. The technique was first described by Thomas W. Sederberg and Scott R. Parry in 1986,[1] and is based on an earlier technique by Alan Barr.[2] It was extended by Coquillart to a technique described as extended free-form deformation, which refines the hull object by introducing additional geometry or by using different hull objects such as cylinders and prisms.[3] Applications
References1. ^{{cite journal|author1=Sederberg, Thomas W.|author2=Parry, Scott R.|title=Free-form deformation of solid geometric models|journal=SIGGRAPH Computer Graphics|volume=20|issue=4|pages=151–160|year=1986|doi=10.1145/15886.15903|citeseerx=10.1.1.396.2148}} 2. ^{{cite book|author=Barr, A. H.|title=Global and local deformations of solid primitives|journal=SIGGRAPH Computer Graphics|volume=18|issue=3|date=July 1984|pages=21–30|doi=10.1145/800031.808573|isbn=978-0897911382}} 3. ^{{cite journal|author=Coquillart, S.|title=Extended free-form deformation: a sculpturing tool for 3D geometric modeling|journal=SIGGRAPH Computer Graphics|volume=24|issue=4|date=September 1990|pages=187–196|doi=10.1145/97880.97900}} 4. ^Nonrigid Registration Using Free-Form Deformations: Application to Breast MR Images External links
3 : Geometry in computer vision|Graphic design|Curves |
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