Understanding Geometric Constraints
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.
Constraint Points
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:
| 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
Constraint bars group together the Geometric Constraints icons associated with an entity.
Example:
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.