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]
↑Sederberg, Thomas W.; Parry, Scott R. (1986). "Free-form deformation of solid geometric models". ACM SIGGRAPH Computer Graphics. Vol.20. pp.151–160. CiteSeerX10.1.1.396.2148. doi:10.1145/15886.15903.
↑Barr, A. H. (July 1984). "Global and local deformations of solid primitives". Proceedings of the 11th annual conference on Computer graphics and interactive techniques. Vol.18. pp.21–30. doi:10.1145/800031.808573. ISBN978-0897911382. S2CID16162806.
