Assembly constraints remove degrees of freedom between selected components. Adaptive components can resize or change shape when constraints are applied.
- Access
- Ribbon:
Assemble tab
Relationships panel
Constrain
, and then click the Assembly tab.
Type and Solutions
Specifies the type of constraint and illustrates the solution used to position components before you apply the constraint. Change constraint type and place constraints when the dialog box is open. When you select a face, curve, or point (including midpoint), an arrow shows the default direction of the solution. Click constraint icons on the dialog box to change solution. Use constraint limits to define the range of allowable movement or rotation. You can specify a maximum, minimum, and resting position value for constraints in the Assembly tab.
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- A
Mate constraint positions components face to face or next to one another with faces flush. Removes one degree of linear translation and two degrees of angular rotation between planar surfaces.
- Mate constraints
- Positions selected faces normal to one another, with faces coincident.
Supports user specified limits and resting position.
- Flush constraint
- Aligns components next to one another with faces flush. Positions selected faces, curves, or points so that they are aligned with surface normals pointing in the same direction.
Supports user specified limits and resting position.
- 2 Axes - Opposed
- Reverses the mate direction of the first selected component so that axes directions are opposed.
- 2 Axes - Aligned
- Aligns components axes with the mate direction of the first selected component.
- 2 Axes Undirected
- Creates an undirected axis constraint using the closest axis.
- Mate constraints
- Angle constrain
- Positions edges or planar faces on two components at a specified angle to define a pivot point. Removes one degree of freedom in rotation or two degrees of angular rotation between planar surfaces.
- Directed Angle
- Solution always applies the right-hand rule. Does not support user specified limits and resting position.
- Undirected Angle
- Allows either orientation, thus resolving situations where component orientation flips during a constraint drive or drag. Supports user specified limits and resting position.
- Explicit Reference Vector
- Explicitly defines direction of Z axis vector (Cross Product) by adding a third pick to the selection process. Reduces tendency of angle constraint to switch to an alternate solution during a constraint drive or drag. This solution is the default. Supports user specified limits and resting position.
- Directed Angle
- Tangent constraint
- A causes faces, planes, cylinders, spheres, and cones to contact at the point of tangency. Tangency can be inside or outside a curve, depending on the direction of the selected surface normal. A tangent constraint removes one degree of linear translation. Between a cylinder and a plane, it removes one degree of linear freedom and one degree of rotational freedom.
- Inside
- Positions the first selected part inside the second selected part at the tangent point. Supports user specified limits and resting position.
- Outside
- Positions the first selected part outside the second selected part at the tangent point. Outside tangency is the default solution. Supports user specified limits and resting position.
- Inside
- Insert constraint
- A combination of a face-to-face mate constraint between planar faces and a mate constraint between the axes of the two components. The Insert constraint positions a bolt shank in a hole. The shank aligns with the hole and the bottom of the bolt head mates with the planar face. A rotational degree of freedom remains open.
- Opposed
- Reverses the mate direction of the first selected component. Supports user specified limits and resting position.
- Aligned
- Reverses the mate direction of the second selected component. Supports user specified limits and resting position.
- Opposed
Selection
Selects geometry on two components to constrain together. You can specify one or more curves, planes, or points to define how features fit together.
You can see the geometry to which a constraint is applied. A color bar on each selection button corresponds to the color of the selected geometry.
If you make a mistake and want to select different geometry, click the appropriate selection command and reselect.
- First Selection
- Selects curves, planes or points on the first component. To end the first selection, click Second Selection or the second face in the graphics window. The first selection is previewed in the same color as the select button color bar in the graphics window.
- Second Selection
- Selects curves, planes, or points on the second component. The second selection is previewed in the same color as the select button color bar in the graphics window
- Third Selection
- Available for Explicit Reference Vector angle constraint. Selects a face, linear edge, work plane, or work axis. The third selection is previewed in the same color as the select button color bar in the graphics window.
- Pick Part First
- Limits the selectable geometry to a single component. Use when components are close to or partially obscure one another. Clear the check box to restore selection mode.
Offset or Angle
Specifies distance by which constrained components are offset from one another.
Use to enter a value equal to a distance or angle that exists in the assembly, but when you do not know the offset or angle. Click the down arrow to measure the angle or distance between components, show dimensions of selected component, or enter a recently used value.
Specify positive or negative values. Default setting is zero. The first picked component determines the positive direction. Enter a negative number to reverse the offset or angle direction.
Show Preview
Shows effect of the constraint on the selected geometry. After both selections are made, underconstrained objects automatically move into constrained positions. Default setting is on. Clear the check box to turn preview off.
If either component is adaptive, constraints are not previewed.
Predict Offset and Orientation
- If the selected component normals (indicated by direction arrows) point in the same direction, a flush constraint is inferred. The offset between them is measured.
- If the selected component normals are opposite, a mate constraint is inferred.
For an angle constraint, with an empty Offset box, the angle is measured and automatically applied.
More
Sets the constraint name and options for assembly constraint limits.
- Name
- Creates a unique name for the constraint in the browser. You can enter a name or leave blank and a default name is automatically created.
- Limits
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- Use Offset As Resting Position
- Sets the offset value as the default position of a constraint with limits. For example, a constraint with a Maximum value of 50-mm, a Minimum of 0-mm and an Offset of 25-mm assumes the 25-mm position after a drag.
Check the box to activate. Clear the check box to deactivate.
- Maximum
- Sets the maximum extent of constraint movement. Check the box to activate. Clear the check box to deactivate. The assigned value is retained when the check box is cleared.
- Minimum
- Sets the minimum extent of constraint movement. Check the box to activate. Clear the check box to deactivate. The assigned value is retained when the check box is cleared.