SURFACES


[User's Guide p. 10-62]

Flat and curved surfaces can be generated automatically from more primitive graphic figures. You typically create a group of graphic figures, and then the surfaces are interpolated from them. It is also possible to describe a curved surface by drawing on e planar facet at a time; however, the automated methods are less tedious and conform to an intuitive understanding of surface types. These methods are highlighted in the examples below. For more details, consult the Microstation Reference manual cited i n [bracketed italics].


Construct Surface by Edges [User's Guide p. 10-100]

Constructing a surface by edges can create a ruled surface between two section curves, or edges. An edge may be a line, line string, shape, arc, curve, B-spline curve, complex chain, or complex shape (we have not yet covered all of these). Also, the edge may be closed (i.e. a loop), or open (i.e. its endpoints do not touch).

Alternatively, Constructing a Surface by edges can generate a surface from four or more adjoining edges. This tool is well suited for generating landscapes, shells such as Saarinen's Kresge Auditorium at MIT, or the complex surfaces of Mireles, Calatrava, or Nervi.


Construct Surface or Solid of Projection [User's Guide p. 10-62]

Constructing a surface or solid of projection will create a surface edge or capped volume (solid) by projecting a boundary edge or shape along a given linear distance. Projection can be done orthogonally, perpendicular to the plane of the edge or shape e lement, or non-orthogonally in any given linear direction. Boundary edges or shapes can be either open or closed, and the generated surface can be either open-ended or a closed, capped volumetric shape.


Construct Tubular Surface [User's Guide p. 10-67]

Constructing a tubular surface will create a surface mesh from a cross-section and a trace curve. The cross-section may either be curved or straight, or a closed shape. The cross-section is "swept" along the path of the trace curve or vector. This is simi lar to the surface of projection, however the tubular surface may trace a curve or other non-uniform or multidirectional path, whereas the projected surface is a simgle linear projection of a given distance. This type of surface may be used to generate an y kind of directional traced-section surface.


Construct Surface or Solid of Revolution [User's Guide p. 10-65]

Constructing a Surface or Solid of Revolution creates a surface by rotating a boundary element around an axis. The boundary element may be any graphic element, curved or straight. This command is similar to the Tubular Surface in that the defining curve i s "swept" along a path. The difference is that surfaces of revolution sweep in a uniform curve around a central axis, whereas Tubular surfaces sweep along any given path, uniform or non-uniform. Surfaces of Revolution are appropriate for th e generation of symmetrical objects with varying cross sections in plan, but uniform sections in profile, such as a dome, a Calatrava column, or a champagne glass.