## The AIM@SHAPE Glossary

### Alphabetical list of terms

- variable-resolution levels-of-detail (lod) model
- It consists of a coarse shape representation and of a set of small modifications, organised into a partial order that allow performing selective refinement in such a way that the resolution be changed on a virtually continuous scale.
- variational modelling
- A paradigm used to find the ?best? curve or surface among all solutions that meet a set of prescribed constraints. The constraints may result from the particular modelling technique used, for example, sample point approximation, or direct curve manipulation. It is typically formulated by minimising some energy functional.
- vertex insertion
- Vertex insertion in a simplicial mesh ?? consists of deleting a connected set of d-simplices from ??, called the region of influence of the vertex insertion, and replacing them with a set of new d-simplices all incident at v . The region of influence is defined by the specific triangulation criterion used.
- vertex removal
- Removal of a vertex v from a simplicial together with all the d-simplices incident at v from a d-dimensional simplicial mesh and re-triangulating the resulting star-shaped region formed by the union of the removed simplices. It is the inverse operation with respect to vertex insertion.
- vertex split
- Expansion of a vertex v in a simplicial mesh into an edge e. A vertex split is the inverse operation with respect to an edge collapse. There are two cases: vertex v is an extreme vertex of e (inverse of half-edge collapse) or not (inverse of a full-edge collapse). In the latter case, any simplex incident in v either expands of one dimension and becomes incident in e, or becomes incident in one of the extreme vertices of e. In the former case, only a subset of simplices incident at v are affected by the vertex split, forming the so-called region of influence (specified in the split operation).
- view
- In a 3D modeller, a view indicates a projection of an object according to some planes, typically the main planes of the coordinate reference system. In the product development process, a view is the product information required by a development phase. Since the various phases of the development process have different goals, they require proper digital model and information of the product itself together with proper tools to treat them. It is therefore necessary to transform the model from one point of view to another one.
- virtual human
- Specialized instance of an articulated character. The model can be synthesised in a variety of ways and can represent a real or a virtual person. VHs are characterized by a set of general attributes (sex, nationality, race, ...), and structural descriptors (skeleton, geometry, landmarks, etc..).
- vision
- The investigation of how the human visual perception works, and how simulating it artificially.
- voxel
- An abbreviation for "volume element" or "volume cell." It is the 3D conceptual counterpart of the 2D pixel. Each voxel is a quantum unit of volume and has a numeric value (or values) associated with it that represents some measurable properties or independent variables of the real objects or phenomena.

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