User manual

39
Point Cloud Basics
A point cloud is a set of data points in a coordinate system. In a three-
dimensional coordinate system, these points represent the external surface of
an object and are usually defined by X, Y, and Z coordinates.
There are five essential terms that are used to describe elements of a given
point cloud: vertices, edges, faces, polygons and surfaces.
Vertices
A vertex is a position. It includes additional
information such as Color, normal vector, and
texture coordinates.
Edges
A connection (i.e. a line) between two vertices is an
edge.
Faces
A face is a closed set of edges. It can be
categorized as a triangle face (three edges) or a
quad face (four edges).
Polygons
If a collection of faces all exist on a single
geometric plane, this one collection of faces is
labeled as a polygon.
Note: Polygons and faces are equivalent in software
platforms that support multi-sided faces. However, most
rendering systems support only 3- or 4-sided faces. So
polygons are represented as multiple faces.
Surfaces
Surfaces connect neighbouring polygons together.
Also called smoothing groups.