Geometric Constraints define relationships that force dependencies and limitations between entities.
There are two types of Geometric Constraints: those that act on a single geometric entity and those that define a relationship between two geometric entities. For example, the Fix, Horizontal, and Vertical Geometric Constraints act on a single entity, whereas Perpendicular, Parallel, Tangent, and others control two entities.
You can apply Geometric Constraints to 2D entities only.
When you use a Geometric Constraint command and move the cursor over an entity, selectable constraint points are indicated with an icon
.
This table lists the entity types to which you can apply Geometric Constraints. Also, it outlines valid constraint points per entity type:
This table lists the entity types that can have Geometric Constraints.
| Entity Type | Constraint Points |
|---|---|
| Line | Endpoints, Midpoint |
| Linear PolyLine segment | Endpoints, Midpoint |
| Circle | Center |
| Arc | Endpoints, Midpoint |
| PolyLine Arc | Endpoints, Midpoint |
| Ellipse | Center |
| Elliptical Arc | Endpoints, Midpoint |
| Spline | Endpoints |
| SimpleNote | Insertion point, Alignment point |
| Note | Insertion point |
| Block | Insertion point |
| AttributeDefinition | Insertion point |
Constraint bars group together the Geometric Constraints icons associated with an entity.

The constraints bar above shows that a horizontal, parallel constraint, collinear, and symmetric constraint are defined for a linear entity.
You can show or hide individual constraint bars, or show or hide them all. Also, you can relocate constraint bars to their default position. See: Controlling the Visibility of Geometric Constraint Icons.