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).
- Select the "Construct Surface
by Edges" tool from the palatte.
- Select first section curve
or edge:
- Select second section curve
or edge:
- Enter data point (left button)
to see the generated surface; Accept or reject the surface.
Note that if the first section curve
is open/closed, than the second section curve must also be open/closed or
a single point.
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.
- Use the "Element Selection" tool
(the arrow) to select all edges.
- Select the "Construct Surface
by Edges" tool from the palatte.
- Accept the surface.
- Select the "Construct Surface
by Edges" tool from the palatte.
- Select edge 1:
- Select all other edges one
by one:
- Enter a data point to display
the surface; Accept or Reject the surface.
Note that the all edges must touch
one another thereby forming a topologically closed path.
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.
- Select the "Construct Surface
or Solid of Projection" tool from the palatte.
- Set TYPE to "Surface" for
an open-ended edge surface, or "Solid" for a capped volume:
- Select whether or not the
projection will be ORTHOGONAL:
- Define a DISTANCE for linear
projection. If none is set the distance will be set interactively:
- Enter a Data point to set
the distance interactively or to accept the pre-set distance:
- Reset to complete the operation.
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.
- Select the "Construct Tubular
Surface" tool from the palatte.
- Set DEFINE BY to "Circular"
if the desired surface is a pipe having a circular cross-section and both
inner and outer radii, or to "Section" to sweep any cross-section along
the trace, changing the sectional orientation along the path.
- Select whether or not the
cross section will always be orthogonal to the trace curve.
- Select the trace curve:
- Select the cross-section curve:
- Enter data point (left button)
to see the generated surface; Accept or reject the 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.
- Select the "Construct Surface
or Solid of Revolution" tool from the palatte.
- Set TYPE to "Surface" for
edges only (open ended), or "Solid" for a closed, capped volume.
- Set the ANGLE that the surface
or solid will sweep.
- Select the boundary element:
- Select first point of the
axis of revolution:
- Select second point of axis
of revolution: (if AXIS is set to "Points").
- Reset to end operation, or
select a data point to continue to revolve.