3D Constructs. Support Geometry

This chapter contains a description of the work of the 3D construction elements and elements of the wire geometry. Auxiliary elements are used for setting the shape of the future body, orientation in space, determining directions, vectors, axes, trajectories, etc. Each element has a separate create and edit command. After running the command, an additional set of icons appears in the auto menu for calling options. Some of the options in this set are shared by all elements.

Common Information about 3D Construction Entities

3D node is one of the basic construction entities used for representing a point in the three-dimensional space. There are several ways of creating 3D nodes. A 3D node can be specified, for instance, as a characteristic point on a body, referencing a vertex, an edge, or a face. It also can be located by using absolute coordinates or offsets from other 3D nodes. 3D nodes can also be specified using the nodes from the two-dimensional drawing, and workplanes. In this way, the 3D node will be defined by selecting one node on a workplane, or two nodes on two different workplanes that are related by having a common projection.12

3D profile is a construction entity used for defining a patch on a surface. A 3D profile is one of the basic entities because it is used as an original reference for many operations. A 3D profile may be defined by an open or closed contour. A closed contour defines a fixed area on the surface that can be used as a base for various operations creating solid bodies. An open profile can be used as a base for creating sheet bodies only as it consists of wire geometry. There are many ways of creating a 3D profile. Thus, it can be drawn on a workplane, or get anew by a variety of modifications to an existing profile, and so on. One 3D profile may contain several contours of the same type. An example of a multi-contour profile is a text entity. A 3D profile can be obtained from hatches and graphic lines (when drawn on the active workplane).

3D Path is a bounded three-dimensional curve with a defined traversal direction. The 3D paths are used in the operations "Sweep", "Pipe", "Loft". A 3D path can be defined by a hatch, 2D paths, as a chain of a body edges, as a curve passing through a sequence of 3D nodes, by modifying existing 3D paths, etc. A 3D path can be closed.

Route is a 3D path consisting of straight line segments smoothly connected by arcs. This command is mainly used for modeling pipes. A large variety of options and controls provided by this command help quickly and easily solving this sort of task.

Workplane is an entity that helps defining the required data for 3D operations, and, first of all, creating 3D profiles. A 3D model cannot be built without creating a workplane. Workplanes can be specified in 2D or 3D window based on various references, such as the 2D drawing views, projections of entities in a 3D model, or the 3D entities themselves, including other workplanes.

Worksurface serves similar functional purposes as the workplanes, providing a non-planar geometrical basis for further design. A worksurface can be a cylinder, a sphere, or a torus.

3D Section is an entity that, generally, results from extruding a planar curve or polyline through all geometry in the direction normal to the plane of the curve. In some cases, a 3D section consists of one or several planes. In this case, it can be used for creating two-dimensional cuts. A 3D section may be included in visualization of the objects of a 3D scene, and can be used in "cut" operations.

Local Coordinate System is an entity for referencing three-dimensional objects in space. It is used for inserting 3D fragments and other elements, copying, exploding of assemblies, etc. This entity is defined by the origin point and the axis directions. Objects snap to a coordinate system by making the object and the target coordinate systems coincide

3D connector – is a special type of local coordinate systems which allows a user, apart from performing the functions of snapping, to automatically tie external variables for jointed parametric elements of the 3D assembly models. This significantly simplifies positioning of parts and parameters assignment when designing the assemblies.

Construction array is a special composite construction element. A construction array is a particularly organized set of copies of an arbitrary construction element, except for sections, light sources and cameras. The copies contributing to such an array can be used as conventional construction elements. Construction arrays are created and edited using any of the 3D array creation operations.