# Add Relations

Create constraints between sketches and sketches, sketches and external elements.

# Add Relations

Click to turn on the Add Constraint command.

Select elements：Select sketch elements in the viewport and fill them into the list automatically. When the mouse points to the edge of the circle, you can directly capture the center of the circle after a short pause.
Existing Constraints：Displays constraints that were automatically added during the drawing process of the selected sketch or generated using the add constraint. When you select an item in the list, the corresponding element in the graphics area is highlighted.
Add Constraint：You can add a constraint to the selected element. The manifest contains only the constraints that the selected element might use.

# Sketch Constraint Description

Restraint	Select the element	The constraint effect created
Horizontal Vertical	One or more lines, or two or more points	Lines become horizontal or vertical, and points are aligned horizontally or vertically
Collinear	Two or more lines, two or more circles, where at least one is the current sketch line and at most one outer element	The selected element is located in the same infinitely long line, with concentric circles or arcs
Equal	Two or more straight lines, two or more arcs	The selected elements are equal in length and radius
Perpendicular	Two straight lines, at least one of which is the current sketch line	The two lines are perpendicular to each other
Parallel	Two or more lines, at least one of which is the current sketch line	The selected elements are parallel to each other
Tangent	Arc, spline, or straight line, which must be the same as the arc or spline	The two elements remain tangential
Point On Curve	Points versus lines, arcs, or splines, and the points must be elements within the current sketch	The point remains on the selected element
Concentric Circle	The starting point of the point, the center of the circle, the line	The two elements remain coincident
Fix	Points, lines	The selected element is fixed in position
Penetrate	Points, lines, and outer curves in the current sketch	Points, lines, and projection points of external elements on the current sketch plane coincide
Crosspoint	Select a point, two lines	The selected point remains coincident at the intersection of the two selected lines
Symmetry	Two lines and a center line	The two lines are symmetrical about the center line