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
In geometry, a cube is a three-dimensional solid object bounded by six square faces, facets or sides, with three meeting at each vertex. Viewed from a corner it is a hexagon and its net is usually depicted as a cross.
The cube is the only r ...
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 curve
A Bézier curve ( ) is a parametric curve used in computer graphics and related fields. A set of discrete "control points" defines a smooth, continuous curve by means of a formula. Usually the curve is intended to approximate a real-world shape t ...
s,
B-spline
In the mathematical subfield of numerical analysis, a B-spline or basis spline is a spline function that has minimal support with respect to a given degree, smoothness, and domain partition. Any spline function of given degree can be expresse ...
s, or
NURB
Non-uniform rational basis spline (NURBS) is a mathematical model using basis splines (B-splines) that is commonly used in computer graphics for representing curves and surfaces. It offers great flexibility and precision for handling both analyt ...
s. The technique was first described by Thomas W. Sederberg and Scott R. Parry in 1986, and is based on an earlier technique by Alan Barr. 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.
Applications
* Free-Form Deformation is used in
computer graphics for solid geometric models. For example, the Lattice Modifier in
Blender (software)
Blender is a free and open-source 3D computer graphics software tool set used for creating animated films, visual effects, art, 3D-printed models, motion graphics, interactive 3D applications, virtual reality, and, formerly, video games. Blend ...
.
* It is used in the
image registration in both rigid and non-rigid
transformation
Transformation may refer to:
Science and mathematics
In biology and medicine
* Metamorphosis, the biological process of changing physical form after birth or hatching
* Malignant transformation, the process of cells becoming cancerous
* Trans ...
.
Nonrigid Registration Using Free-Form Deformations: Application to Breast MR Images
archived
"Nonrigid Registration using Free-Form Deformations: Application to Breast MR Images"
References
External links
C++ Library
Geometry in computer vision
Graphic design
Curves
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