Use the Constraints toolbox to define relationships between sketch elements and reference planes.
The Constraints toolbox includes:
Fixed Horizontal Vertical Perpendicular Tangent Coincident Midpoint Symmetry Parallel Concentric Equal Radius Equal Length Equal Distance Auto Constraints
Fixed
Select a 2D edge or point to prevent it from moving. For an edge, this does not fix the locations of its endpoints unless "Fix Endpoints" is checked. They can still move along the curve. Endpoints may also be selected to apply a Fixed constraint to them after which they can no longer move. When a point is selected to make it Fixed, all points coincident to it are also made Fixed.
Horizontal
Select a straight line. The Horizontal constraint forces a selected line to a position parallel to the X-axis.
If an ellipse, or elliptical arc is selected, its major axis will be forced parallel to the X-axis.
Constraints Toolbox
Vertical
Select a straight line. The Vertical constraint forces a selected line to a position parallel to the Y-axis. If you select an ellipse, or elliptical arc, its major axis will be forced parallel to the Y-axis.
Perpendicular
Select two edges as close as possible to the location where they, or their extensions, would cross. The Perpendicular constraint ensures that, where the two edges cross, they (or if curves, their tangents) are at 90° to each other. Using preselect, you can select an edge and a series of other edges to be perpen-dicular to the first edge before selecting this function.
For Perpendicular constrains on Splines, the curves need to be very close to perpendicular prior to the constraint or the constraint “may not be processed, or may give unexpected results”. In cases like this, look to see if there are extra, unneeded constraints on the spline or its endpoints and remove those if needed, likewise make sure the spline is “Flexible”. If these steps do not help, then try using a tangent constraint instead as tangent constraints are more reliable when working on splines.
Tangent
Select two edges as close as possible to the location where they are to be tangent. The selection location controls which side of a circle the Tangent constraint applies. Also, the tangency can occur outside of the displayed portion of a curve. For example, a line can be made tangent to a circle that is far from it.
Using preselect, you can select an edge and a series of other edges to be tangent to the first edge before selecting this function.
Coincident
Select two points, two edges, or a point and an edge as near as possible to the location you want them to be coincident. The coincident location can be outside the displayed portion of either edge. For ex-ample, you can make a point coincident with a line even though the point does not lie on the displayed line segment. Using preselect, you can select an edge and a series of other edges to be coincident to the first edge before selecting this function. The selected edges must be of the same type, or one of them must be a point. You cannot make two splines coincident.
If you have two or more points that are at, or near the same location and you want to assign them as all coincident, a good way to do it is to preselect using box selection with only points allowed for selec-tion. Then go to Coincident and constraints will be created to make them all coincident.
Midpoint
Select a point and a line. The Midpoint constraint forces the point to be on the line an equal distance from the line endpoints. You can preselect a series of point-line pairs before selecting this function.
Symmetry
Right Mouse Button Context Menu: Select new symmetry axis
First select a line to be the symmetry axis, then a pair of points or edges (of the same type) to be symmetric about the axis. If you want the endpoints of the curves to also be symmetric, you need to add symmetry constraints to them as well.
You may continue to select pairs of points or edges (of the same type) to be symmetric about the axis you already have selected. Use the right mouse button option. Select new symmetry axis when you want to select a new axis. Axis and pairs of points or edges (of the same type) may also be preselected before entering the function.
Parallel
Right Mouse Button Context Menu: Select pairs, Select multiple, New multiple select
The default right mouse button option, Select pairs, allows you to select a pair of 2D straight edges, such as lines. The Parallel constraint forces the selected lines or major axes for ellipses and elliptical arcs to be parallel. The right mouse button option, Select multiple, allows you to select a continuing series of lines or ellipses. In the series, after you have selected two edges, a constraint is created and then the second edge you selected is used as the first edge for the next pair. This continues until you either use the right mouse button to start a new series or return to standard pairs selection. A series of these may be preselected before selecting the function and they are treated like a series selected in 'Select multiple' mode.
Concentric
Right Mouse Button Context Menu: Select pairs, Select multiple, New multiple select
The default right mouse button option, Select pairs, allows you to select two points, circles, circular arcs, ellipses, or elliptical arcs. The Concentric constraint will force selected points, or centers to be at the same location. For circles, circular arcs, ellipses, or elliptical arcs, they do not need to have an actual center point. The right mouse button option, Select multiple, allows you to select a continuing series of points, circles, circular arcs, ellipses, or elliptical arcs. In the series, after you have selected two edges, a constraint is created and then the second edge you selected is used as the first edge for the next pair. This continues until you either use the right mouse button to start a new series or return to standard pairs selection. A series of these may be preselected before selecting the function and they are treated like a series selected in 'Select multiple' mode.