## The AIM@SHAPE Glossary

### Alphabetical list of terms

- landmark
- A place holder to store information associated to a particular location on a 3D geometry. Landmarks can be anatomical structures used as a point of origin to locating other anatomical structures, or points from which measurements can be taken.
- laser scanner
- Device that emits highly amplified and coherent radiation of one or more discrete frequencies (e.g. a Linear Camera).
- level of articulation
- Term used in the H-Anim standard related to the degrees of freedom of a skeleton chain. LOA is also used relatively to LOD, with respect to multi-resolution for bone-based animation.
- level set (of a real function f)
- The level set of a real function f is the pre-image through f of a constant value t in the domain of f. The level sets are also called contours or iso-levels. Level sets may be non-connected.
- levels-of-detail (lod)
- Compact description of several representations of a shape, from which representations of a shape at different levels of resolution can be obtained.
- linear axis
- It is based on a linear wave-front propagation like the straight skeleton, but the discrepancy in the speed of the points in the propagating wave-front, though never zero, can decrease as much as wanted.
- linear static problem
- Linear static analysis deals with continuum static problems in which the response is linear in the cause-and-effect sense.
- line of curvature
- A surface curve whose tangent directions coincide with those of the principle directions. The lines of curvature form an orthogonal net everywhere on the surface except the umbilical points where the principal directions are not defined.
- line of sight
- The straight line between the observer and the target.
- loa
- See Level of Articulation.
- lod
- See Levels of Detail.
- loop scheme
- A subdivision scheme for triangle meshes generalizing the three directional box spline.
- l-system
- Lindenmayer system. A string rewriting system which can be used to generate fractals with dimension between 1 and 2.
- l-system surface
- A surface built within a L-system.

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