Free-form deformation

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

• Free-Form Deformation is used in computer graphics for solid geometric models. For example, the Lattice Modifier in Blender (software).
• It is used in the image registration in both rigid and non-rigid transformation.^[4]