Use geometric constraints
to constrain and restrict surfaces. And use mathematical expressions
to derive surface properties.
Use Geometric Constraints
with Surface Profiles
Just
as with 2D drafting, geometric constraints can be used to restrict
the movement of 3D surfaces. For example, you can specify that a
surface remain fixed in a perpendicular or parallel location to
another object. In the example below, an offset surface is locked
in a parallel position to its original surface.
Constraints are applied
to the 2D profile object used to create the surface, not the surface
itself. Use selection cycling to be sure that you are selecting
the profile curve and not the surface or the edge subobject. See Apply or Remove Geometric Constraints.
Use Mathematical Expressions
to Derive Surface Properties
Dimensional
constraints are user-defined expressions that are applied in the properties
palette for that surface.
For a complete list of
operators and functions allowed in expressions, see Control Geometry with the Parameters Manager.
The following table lists the surface types and their properties
that accept expressions
| Type of Surface |
Surface properties that can be constrained. |
| Blend Surface |
Bulge Magnitude |
| Extend Surface |
Extension Distance |
| Extruded Surface |
|
| Fillet Surface |
Fillet Radius |
| Loft Surface |
Bulge Magnitude |
| Network Surface |
Bulge Magnitude |
| Offset Surface |
Offset Distance |
| Patch Surface |
Bulge Magnitude |
| Revolve Surface |
Revolve Angle |
To create a parallel relationship
between two surfaces
- Enter dsettings and
select the Selection Cycling tab.
- Click Allow Selection Cycling to turn
selection cycling on.
- Enter geomconstraint.
Enter pa to select the parallel option.
- Select the first and second profile objects.
Be careful not to select the surface or the edge subobject.
If the surfaces were
not already parallel, they are moved into a parallel location and
the parallel constraint symbol appears.
To add a user expression
to specify the height of a surface
- Right-click on a surface and select Properties.
The properties palette
displays.
- In the Geometry section,
enter an expression in the Height field.
A symbol appears next
to that field to indicate that a dimensional constraint is applied
to this property.
CommandsAUTOCONSTRAIN
Applies geometric constraints
to a selection set of objects based on orientation of the objects
relative to one another.
CONSTRAINTBAR
Displays or hides the
geometric constraints on an object.
CONSTRAINTSETTINGS
Controls the display
of geometric constraints on constraint bars.
DCDISPLAY
Displays or hides the
dynamic constraints associated with a selection set of objects.
DELCONSTRAINT
Removes all geometric
and dimensional constraints from a selection set of objects.
DIMCONSTRAINT
Applies dimensional
constraints to selected objects or points on objects, or converts
associative dimensions to dimensional constraints.
GEOMCONSTRAINT
Displays or hides the
geometric constraints on an object.
LIST
Displays property data
for selected objects.
MEASUREGEOM
Measures the distance,
radius, angle, area, and volume of selected objects or sequence
of points.
PARAMETERS
Controls the associative
parameters used in the drawing.
-PARAMETERS
Controls the associative
parameters used in the drawing.
PARAMETERSCLOSE
Closes the Parameters
Manager palette.
TEXTEDIT
Edits a dimensional
constraint, dimension, or text object.
System VariablesCCONSTRAINTFORM
Controls whether annotational
or dynamic constraints are applied to objects.
CONSTRAINTBARDISPLAY
Controls the display
of constraint bars after you apply constraints and when you select
geometrically constrained drawings.
CONSTRAINTBARMODE
Controls the display
of geometrical constraints on constraint bars.
CONSTRAINTNAMEFORMAT
Controls the text format
for dimensional constraints.
CONSTRAINTRELAX
Indicates whether constraints
are enforced or relaxed when editing an object.
CONSTRAINTSOLVEMODE
Controls constraint
behavior when applying or editing constraints.
DIMCONSTRAINTICON
Displays the lock icon
next to the text for dimensional constraints.
DYNCONSTRAINTMODE
Displays hidden dimensional
constraints when constrained objects are selected.
PARAMETERCOPYMODE
Controls how constraints
and referenced user parameters are handled when constrained objects
are copied between drawings, Model space and layouts, and block
definitions.
PARAMETERSSTATUS
Indicates whether the
Parameters Manager is displayed or hidden.
SURFACEASSOCIATIVITY
Controls whether surfaces
maintain a relationship with the objects from which they were created.
