# Constraints

Constraints are used to define the spatial relationship between entities or parameters of entities themselves. Some constraints such as distance or angle allow entering a value.

Some constraints can have a workplane. Unless otherwise noted, this means that the constraint applies in the workplane, that is all entities are projected onto the workplane.

In general, constraints are created by selecting the to be constrained entities and invoking the requisite tool. Constraints can only be created if at least one of the selected entities is in the current group to prevent creating redundant or conflicting constraints.

## Points coincident

Constrains two points to be at the same position.

- Workplane:
optional

- Selection:
Two points

- Tool:
Constrain coincident

## Point on line

Constrains a point to be on a line. Keep in mind that lines are infinite from the constraint’s point of view.

- Workplane:
optional

- Selection:
Line (2D or 3D), point

- Tool:
Constrain point on line

## Point on bezier

Constrains a point to be on a bezier curve. Even though the bezier curve is only drawn for 0 ≤ t ≤ 1, t can fall outside of this range for this constraint.

- Workplane:
required

- Selection:
Bezier curve, point

- Tool:
Constrain point on bezier

Since version 1.2

## Midpoint

Constrains a point to be at the midpoint of a line.

- Workplane:
optional

- Selection:
Line (2D or 3D), point

- Tool:
Constrain midpoint

## Point/line distance

Constrains the distance from a point to a line to be the entered value. The distance between a point and a line is the shortest path between the two, i.e. a line perpendicular to the line passing through the point.

- Workplane:
optional

- Selection:
Line (2D or 3D), point

- Tool:
Constrain point/line distance

## Point on circle

Constrains a point to be on a circle or an arc. From the constraint’s point of view, arcs are full circles.

- Workplane:
none

- Selection:
Arc/Circle (2D or 3D), point

- Tool:
Constrain point on circle

## Point in plane

Constrains a point to be in a plane defined by two lines.

- Workplane:
none

- Selection:
Two lines, point

- Tool:
Constrain point in plane

## Point in workplane

Constrains a point to be in a workplane

- Workplane:
none

- Selection:
Workplane, point

- Tool:
Constrain point in workplane

Since version 1.1

## Point/plane distance

Constrains a point’s distance from a plane defined by two lines to be the entered value.

- Workplane:
none

- Selection:
Two lines, point

- Tool:
Constrain point/plane distance

## Distance

Constrains the (Euclidean) distance between two points to the entered value. Selecting a line is equivalent to selecting its endpoints.

- Workplane:
optional

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain distance

## Aligned distance

Constrains the (euclidean) distance between two points projected onto the alignment entity to be the entered value. Selecting a line is equivalent to selecting its endpoints.

- Workplane:
optional

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain aligned distance

The tool is special in the way that it’s interactive. After invoking the tool, click on the entity the distance vector should be aligned to. This can be either a line (2D or 3D) or a workplane. Selecting a workplane uses its normal vector.

Since version 1.2

## Horizontal / Vertical distance

Constrains the horizontal/vertical distance between two points to the entered value. Selecting a line is equivalent to selecting its endpoints.

- Workplane:
required

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain horizontal distance, Constrain vertical distance

## Horizontal / Vertical

Constrains two points to be at the same X position (vertical) or to be at the same Y position (horizontal). Selecting a line is equivalent to selecting its endpoints.

- Workplane:
required

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain horizontal, Constrain vertical

## Symmetric horizontal / vertical

Constrains two points to be symmetric about the vertical sketch axis (horizontal) or to be at symmetric about the horizontal sketch axis (vertical). Selecting a line is equivalent to selecting its endpoints.

- Workplane:
required

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain symmetric horizontally / vertically

Since version 1.1

## Symmetric about line

Constrains two points to be symmetric about a line. Selecting a line is equivalent to selecting its endpoints.

- Workplane:
required

- Selection:
Two points or a line (2D or 3D)

- Tool:
Constrain symmetric about line

Select the line the symmetry applies to in the tool.

Since version 1.1

## Diameter / Radius

Constrains the diameter or radius of a circle or an arc to the entered value.

- Workplane:
none

- Selection:
Arc or circle

- Tool:
Constrain diameter, Constrain radius

## Equal length

Constrains two or more lines to have the same length.

- Workplane:
optional

- Selection:
Two or more lines (2D or 3D)

- Tool:
Constrain equal length

## Equal radius

Constrains two or more arcs or circles to have the same radius.

- Workplane:
optional

- Selection:
Two or more arcs or circles

- Tool:
Constrain equal radius

## Workplane normal

Constrains workplane’s orientation to a plane defined by two lines.

- Workplane:
none

- Selection:
The to-be constrained workplane

- Tool:
Constrain workplane normal

The tool is special in the way that it’s interactive. After invoking the tool, first click on the line that should define the workplane’s X axis, then on another line with a shared point to define the plane. Both lines must be in a group before the workplane.

## Perpendicular

Constrains two lines to be perpendicular with respect to each other.

- Workplane:
optional

- Selection:
Two lines (2D or 3D)

- Tool:
Constrain perpendicular

## Line/points perpendicular

Constrains a line to be perpendicular to the vector between two points.

- Workplane:
none

- Selection:
Line (3D only) and two points

- Tool:
Constrain line/points perpendicular

## Angle

Constrains the angle between two lines to the entered value.

- Workplane:
optional

- Selection:
Two lines (2D or 3d)

- Tool:
Constrain angle

## Curve/Curve tangent

Constrains two arcs or bezier curves to be tangent at a shared point.

- Workplane:
none

- Selection:
Two arcs or two bezier curves or arc and bezier curve

- Tool:
Constrain curve/curve tangent

This constraint used to be called Arc/Arc tangent in versions prior to 1.2.

## Arc/Line tangent

Constrains a line and an arc to be tangent at a shared point.

- Workplane:
none

- Selection:
Point at which arc and line coincide

- Tool:
Constrain arc/line tangent

## Bezier/Line tangent

Constrains a line and a bezier to be tangent at a shared point.

- Workplane:
none

- Selection:
Point at which bezier curve and line coincide

- Tool:
Constrain bezier/line tangent

Since version 1.2

## Bezier/Bezier tangent symmetric

Constraints the tangents of two bezier curves to be symmetric at a shared point

- Workplane:
none

- Selection:
Point at which the two bezier curves coincide

- Tool:
Constrain tangent to be symmetric

Since version 1.2

## Parallel

This constraint can do two things:

Constrains two lines to be parallel.

- Workplane:
none

- Selection:
Two lines (2D or 3D)

- Tool:
Constrain parallel

Constrains a line to be parallel to the normal vector of a workplane

- Workplane:
none

- Selection:
Line (3D only) and workplane

- Tool:
Constrain parallel

## Same orientation

Constrains two workplanes/STEP models to have the same orientation. There’s still one hidden degree of freedom along the normal in increments of 90°. Use the Rotate tool to get the entity to the target orientation.

- Workplane:
none

- Selection:
Two entities of these types: workplane, STEP model, document

- Tool:
Constrain same orientation

## Lock rotation

Locks the STEP model/workplane to the rotation set in the “Rotate” tool. Even with the constraint applied, the rotate tool can still be used.

- Workplane:
none

- Selection:
One workplane, STEP model or document

- Tool:
Lock rotation