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Geometric objects |
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Geometric objects are composed of primitives. Primitives are:
•vertex,
•edge,
•face.
vertex is a primitive representing a point or end of the edge. A particular case of the vertex is a zero length edge (for example, a vertex of the cone).
Edge is a primitive representing a segment of the curve or of the boundary line of the face limited by vertices and not containing other vertices within itself. In particular cases, an edge may not be limited by vertices (closed edges).
Face is a primitive representing a part of the surface or a surface limited by edges and not containing other edges within itself. In particular cases, a face may not be limited by edges (for example, spherical or toroidal faces).
Such objects as planes and axes do not have primitives.
Other objects depending on their type are composed of one or several primitives. For example, a "point" object consists of one vertex, broken lines and sketches – of edges and vertices, solids – of edges, vertices and faces.
Solid is a model object that has certain volume and relates to some material. A solid does not have separate file representation.
A solid is generally a total of faces, edges and vertices. In a particular case, a solid may be represented by one face (for example, a spherical or toroidal solid).
Faces of the solid make a closed surface. A breach in the closure results in the solid’s compromised integrity.
Building of solids in the model is described in section Solids.
Sheet solid is a special kind of solids. They are designed for modeling parts obtained from sheet material using bending operations. Building of sheet solids is described in section Sheet Solids.
Surface is a geometric object represented by an associated total of faces or one face. Faces of the surface cannot be faces of any other objects (other surfaces, solids).
Building of surfaces is described in section Surfaces.
Polygonal object – a model object representing surface data in the form of triangulation mesh. Working with polygonal objects is described in section Polygonal objects.
Sketch is an object three-dimensional modeling created on the plane or flat face with the use of a drawing and graphic editor.
Sketches are used in some operations. For example, a sketch may set a section shape of the solid obtained with an extrusion operation, a rib contour, etc.
Sketch requirements are determined by the operation in which it is used.
Building of sketches is described in section Sketches.
Objects of construction geometry are:
•coordinate systems,
•coordinate and constructive planes,
•coordinate and constructive axes,
•control points,
•attachment points.
Building of objects of construction geometry in the model is described in section Construction objects.
