Create mesh forms by
filling the space between other objects such as lines and arcs.
You
can use a variety of methods to create mesh objects whose edges
are defined by other objects. The MESHTYPE system variable
controls whether the new objects are valid mesh objects, or whether
they are created using legacy polyface or polygon geometry.
You
can control whether the mesh is displayed as a wireframe, hidden,
or conceptual image by changing the visual style (VISUALSTYLES).
Types of Meshes Created
from Other Objects
You
can create several types of meshes that are based on existing objects.
- Ruled mesh. RULESURF creates a mesh
that represents the ruled surface between two lines or curves.
- Tabulated mesh. TABSURF creates a mesh
that represents a general tabulated surface. The surface is defined
by the extrusion of a line or curve (called a path curve) in a specified
direction and distance (called a direction vector or path).
- Revolved mesh. REVSURF creates a mesh
that approximates a surface of revolution by rotating a profile
about a specified axis. A profile can consist of lines, circles,
arcs, ellipses, elliptical arcs, polylines, splines, closed polylines,
polygons, closed splines, and donuts.
- Edge-defined mesh. EDGESURF creates a mesh
approximating a Coons surface patch mesh from four adjoining edges.
A Coons surface patch mesh is a bicubic surface that is interpolated
between four adjoining edges (which can be general space curves).
Create a Ruled Mesh
There
are several methods for creating meshes.
With RULESURF, you create
a mesh between two lines or curves. Use two different objects to
define the edges of the ruled mesh: lines, points, arcs, circles, ellipses,
elliptical arcs, 2D polylines, 3D polylines, or splines.
Both objects that are
used as the “rails” of a ruled mesh must be either open or closed.
You can pair a point object with either an open or a closed object.
You
can specify any two points on closed curves to complete the operation. For
open curves, construction of the ruled mesh is based on the locations
of the specified points on the curves.
Create a Tabulated Mesh
With the TABSURF command, you
can create a mesh that represents a general tabulated surface defined
by a path curve and a direction vector. The path curve can be a
line, arc, circle, ellipse, elliptical arc, 2D polyline, 3D polyline,
or spline. The direction vector can be a line or an open 2D or 3D polyline.
TABSURF creates the mesh
as a series of parallel polygons running along a specified path.
The original object and the direction vector must already be drawn,
as shown in the following illustrations.
Create a Revolved Mesh
Use the REVSURF command to create
a revolved mesh by rotating a profile of the object about an axis.
REVSURF is useful for mesh forms with rotational symmetry.
The profile is called
a path curve. It can consist of any combination of lines, circles,
arcs, ellipses, elliptical arcs, polylines, splines, closed polylines,
polygons, closed splines, or donuts.
Create an Edge-Defined
Mesh
With the EDGESURF command, you
can create a Coons surface patch mesh, as shown
in the following illustration, from four objects called edges.
Edges can be arcs, lines, polylines, splines, or elliptical arcs
that form a closed loop and share endpoints. A Coons patch is a
bicubic surface (one curve in the M direction
and another in the N direction) interpolated between
the four edges.
To create a ruled mesh
- Select an object to
act as the first defining curve.
- Select a second object
as the second defining curve.
Mesh segments are drawn
between the defining curves. The number of segments equals the value
set for SURFTAB1.
- Erase the original
curves if necessary.
To create a tabulated mesh
- Specify an object to
define the overall shape of the tabulated surface (the path curve).
The object can be a line,
arc, circle, ellipse, or a 2D or 3D polyline.
- Specify an open line
or polyline that defines the direction vector.
The mesh is extended
from the start point to the endpoint of the direction vector.
- Erase the original
objects if necessary.
To create a revolved mesh
- Specify an object to
define the path curve.
The
path curve, which defines the N direction
of the mesh, can be a line, arc, circle, ellipse, elliptical arc,
2D polyline, 3D polyline, or spline. If you select a circle, closed
ellipse, or closed polyline, the mesh is closed in the N direction.
- Specify an object to
define the axis of revolution.
The
direction vector can be a line or an open 2D or 3D polyline. If
you choose a polyline, the vector sets the rotation axis from its
first vertex to its last vertex. Any intermediate vertices are ignored.
The axis of revolution determines the M direction
of the mesh.
- Specify the start angle.
If
you specify a nonzero start angle, the mesh is generated at a position offset
from the path curve by that angle.
- Specify the included angle.
The included angle specifies
how far the mesh extends around the axis of revolution.
- Erase the original
objects if necessary.
To create an edge-defined
Coons surface patch mesh
- Select four objects
to define the four adjoining edges of the mesh patch.
The objects can be arcs,
lines, polylines, splines, or elliptical arcs that form a closed
loop and share endpoints.
The
first edge you select determines the M direction
of the mesh.
CommandsEDGESURF
Creates
a mesh between four contiguous edges or curves.
PEDIT
Edits
polylines and 3D polygon meshes.
PFACE
Creates a 3D polyface
mesh vertex by vertex.
REVSURF
Creates
a mesh by revolving a profile about an axis.
RULESURF
Creates
a mesh that represents the surface between two lines or curves.
TABSURF
Creates a mesh from
a line or curve that is swept along a straight path.
VISUALSTYLES
Creates and modifies
visual styles and applies a visual style to a viewport.
System VariablesFACETRATIO
Controls the aspect
ratio of faceting for cylindrical and conic solids.
MESHTYPE
Controls the type of
mesh that is created by REVSURF, TABSURF, RULESURF and EDGESURF.
PLINECONVERTMODE
Specifies the fit method
used in converting splines to polylines.
PFACEVMAX
Sets the maximum number
of vertices per face.
SURFTAB1
Sets the number of tabulations
to be generated for the RULESURF and TABSURF commands.
SURFTAB2
Sets the mesh density
in the N direction for the REVSURF and EDGESURF commands.
SURFTYPE
Controls the type of
surface-fitting to be performed by the Smooth option of the PEDIT
command.
SURFU
Sets the surface density
for PEDIT Smooth in the M direction and the U isolines density on
surface objects.
SURFV
Sets the surface density
for PEDIT Smooth in the N direction and the V isolines density on
surface objects.