Constraints are frequently used in AutoCAD for proper designing.

This Constrains are different types they are.

- Endpoint Tangent
- Midpoint Nearest
- Center Apparent Intersection
- Node Parallel
- Quadrant
- Intersection
- Extension
- Insertion
- Perpendicular

**Endpoint:**

The endpoint is used for selecting line of end point to construct line.

**Midpoint:**

This method is useful for selecting the point from the line center. If we need to draw a line or any section from the center of line this midpoint method is used.

**Center: **

To select the circle center point by using center constrain. It is helpful draw a circle or line from the center of the circle without using work coordinate system.

**Extension:**

If line is needs to be extended then the extension method is used.

** ****Perpendicular:**

To draw a perpendicular line from the existing line then perpendicular constrains is used.

**Tangent:**

The tangent method is helpful for attach a line to the circle surface. To draw a line from surface of circle it is not created so then the tangent method is used.

**Parallel:**

To draw similar lines then parallel constrain is used.