# Add Relations

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

# Add Relations

Click to open the Add Constraint command.

Select elements: Select sketch elements in the viewport and fill them into the list automatically.
Existing constraints: Displays constraints that were automatically added to the selected sketch during drawing or generated using Add constraints. When an item is selected in the list, the corresponding element in the drawing area is highlighted.
Add constraints: You can add constraints to the selected element. The list contains only the constraints that may be used by the selected element.

# Sketch constraint description

constraints	Select elements	Create a constraint effect
Along X	One or more straight lines	The lines change to be parallel along the axis
Along Y	One or more straight lines	The lines change to be parallel along the axis
Along Z	One or more straight lines	The lines change to be parallel along the axis
Collinear	Two or more lines, two or more circles, of which at least one is the current sketch line, and at most one external element	The selected element is located on the same line of infinite length, with the circle or arc concentric
Equal	Two or more straight lines, two or more arcs	The selected elements are equal in length and radius
Vertical	Two straight lines, at least one for the current sketch line	The two lines are perpendicular to each other
Parallel	Two or more lines, at least one for the current sketch line	The selected elements are parallel to each other
Point On Curve	Points with straight lines, arcs, or splines, points must be elements within the current sketch	Points remain on the selected element
Overlap	Point, center of circle, starting point of line	The two elements remain coincident
Penetrate	Points, lines and external curves in the current sketch	The points and lines in the sketch coincide with the projection points of the external elements on the datum of the current sketch
Tangency	Arc, spline curve or straight line, the straight line must be with the arc or spline curve	The two elements remain tangent
Concentric Circle	Two or more circles or arcs	The centers of the selected circles or arcs coincide
Fixed	Lines, circles, arcs, points	The selected element is fixed in position
Intersections	Choose one point and two lines	The selected point coincides with the intersection of the two selected lines
Symmetry	Two lines and a center line	The two lines are symmetrical about the center line