Apply or Remove Geometric
associate geometric objects together, or specify a fixed location
NoteThis topic has been included for AutoCAD-compatibility
purposes only. In AutoCAD LT, parametric drawing technology is limited
to displaying and hiding constraints, editing constrained geometry,
and changing values in the Parameters Manager.
example, you can specify that a line should always be perpendicular
to another one, that an arc and a circle should always remain concentric,
or that a line should always be tangent to an arc.
When you apply a constraint,
two things occur:
- The object that you select adjusts automatically
to conform to the specified constraint
- By default, a gray constraint icon displays
near the constrained object as shown in the previous illustration,
and a small blue glyph displays with your cursor when you move it
over a constrained object
Once applied, constraints
permit only those changes to the geometry that do not violate the
constraints. This provides a method for exploring design options
or making design changes while maintaining the requirements and
specifications of the design.
NoteThe order in which
you select two objects when you apply a constraint is important
in some cases. Normally, the second object you select adjusts to
the first object. For example, when you apply a perpendicular constraint,
the second object you select will adjust to become perpendicular
to the first.
You can apply geometric
constraints to 2D geometric objects only. Objects cannot be constrained
between model space and paper space.
Specify Constraint Points
some constraints, you specify constraint points on
objects instead of selecting the objects. This behavior is similar
to that of object snaps, but the locations are limited to endpoints,
midpoints, center points, and insertion points.
For example, a coincident
constraint can restrict the location of the endpoint of one line to
the endpoint of another line.
The following glyph is
displayed on the object as you roll over the object.
You use this glyph to
confirm whether you are specifying the intended point to constrain.
The fix, horizontal,
and vertical constraint icons indicate whether the constraints are applied
to an object or a point.
The symmetric constraint
icons indicate whether it identifying a symmetrical point or object,
or the symmetrical line.
When rolling over any
icon, the constraint point markers are displayed indicating the
constrained points. You do not need to roll over the icon to identify
the constraints that are applied to the points of the selected object.
A different set of constraint
bar icons are displayed when a horizontal or vertical constraint
is not parallel or perpendicular with the current UCS.
Use Fix Constraints
fix constraint associates a constraint point on an object, or the
object itself with a fixed location with respect to the World Coordinate
It is often advisable
to specify a fix constraint at an important geometric feature. This locks
the location of that point or object, and prevents geometry from
relocating when you make changes to the design.
When you fix an object,
the angle of a line, or the center of an arc or circle is also fixed.
Apply Multiple Geometric
can apply multiple geometric constraints to objects either manually
When you want to apply
all essential geometric constraints to a design automatically, you can
use AUTOCONSTRAIN with the objects
that you select in your drawing. This helps constrain the geometric
shape of the design—depending on your design, there might be cases
where you need to apply additional geometric constraints.
AUTOCONSTRAIN also provides
settings in which you can specify the following options:
- What geometric constraints to apply
- What order to apply geometric constraints
- What tolerances are used to determine
whether objects are horizontal, vertical, or touching
NoteFix constraint is
not applied with AUTOCONSTRAIN. You must apply the constraint individually.
Equal constraint applied with AUTOCONSTRAIN resizes the selected
arcs to the same radius only. It is not applied to the arc length.
To fully constrain the
size and proportions of a design, you will later need to apply dimensional
Remove Geometric Constraints
geometric constraint cannot be modified, but you can delete it and
apply a different one. Several constraint options, including Delete,
are available from the shortcut menu that is displayed when you
right-click a constraint icon in the drawing.
You can delete all constraints
from a selection set in a single operation with DELCONSTRAINT.
Displays or hides the
geometric constraints on an object.
Controls the display
of geometric constraints on constraint bars.