Mates: Frequently Asked Questions

Changing, Deleting, or Suppressing Mates

Answers: Managing Mates

  1. Why can I not have redundant dimensions or distance mates?
    The software treats dimensions as parametric, modifiable entities. If you can add dimensions to entities already defined by relations or mates, you can violate the relations or mates by modifying the dimension. For example:
    Fully defined sketch.
    Redundant perpendicular relation added. Sketch is still fully defined.
    Redundant dimension added. Sketch is over defined.

    Changing the dimension later to something other than 90° can conflict with the relations. To prevent this potential conflict, the software makes the sketch over defined, requiring you to delete the dimension, make the dimension driven, or delete the relations.

    Resolving conflicts are more difficult when redundant relations exist. You need to delete the perpendicular relation and the adjacent horizontal or vertical relation. The SketchXpert functionality displays all possible solutions.

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  2. What are the best practices to follow to set up mates?
    To Maximize... Use this technique...
    Robustness and Performance Mate components to a common component for optimum performance.

    Robustness Use face-to-face mates, if your design intent permits, because they are more robust and predictable.
    Performance Use subassemblies to limit the number of top-level mates. The application solves all top level mates when it rebuilds an assembly.

    Click Performance Evaluation (Tools toolbar) to display assembly statistics.

    Efficiency when adding mates
    • Use mate references if your models use similar components that you need to replace regularly. Click Mate Reference (Reference Geometry toolbar) and set the mates.
    • Use Smart Mates.

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  3. How do I know what mates are on a part?
    In the assembly's FeatureManager design tree, do one of the following:
    • Right-click a component and click View Mates.
    • Right-click the assembly feature and click Tree Display > View Mates and dependencies. Expand components to see the mates.

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  4. What do I do if I get a mate I don't want?
    Use these techniques:
    • Click Undo if you have not yet closed the Mate PropertyManager.
    • Suppress the mate. Right-click the mate in the FeatureManager design tree, click Properties, and then click Suppressed.
    • Use MateXpert to diagnose and resolve mating problems. Click Tools > Evaluate > MateXpert.
    • Check the Mate alignment on the Standard, Advanced, or Mechanical tabs in the Mate PropertyManager.

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  5. What do I do if my mate combinations cause errors or move parts in unexpected ways?
    Use these techniques:
    • You may have conflicting mates. Use MateXpert to check for conflicting mates, then delete or edit one of the conflicting mates. Click Tools > Evaluate > MateXpert .
    • You may have an improper Mate alignment. Edit the mate and in the Mate PropertyManager, click Aligned or Anti-Aligned for Mate alignment.
    • Use MateXpert to diagnose and resolve mating problems. Click Tools > Evaluate > MateXpert.
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  6. When I add a mate, my parts do not move as expected. Why?

    When you mate to an analytical surface, a valid solution is to mate to the virtual extension of the analytical surface. The components might not move as you expect.

    To try to achieve the mate, move the components as close to the correct position as possible.

    In this assembly, you want to place the lever's edge on the half cylinder.
    Original Position Required Position
    Select entities to mate. Position after the mate is applied. Why does the lever move here?
    The lever mates to the virtual extension of the analytical surface, shown in red.
    Move the lever closer to the correct position, then apply the mate. The lever mates to the correct position.

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  7. A component does not move when I try to drag it. Why?
    • Check if the part has mates that restrict movement. A tooltip appears if the part is fully defined.
    • Check if the part is fixed. A tooltip appears at the selected location if the part is fixed.
    • Try dragging the part from a different spot.
    • Check the mates because the setup may be incorrect.
    • For a mechanism, try dragging a different part.
    • Sometimes you cannot move a part by dragging it. Try adding a mate to move the part.

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  8. Does the order I apply constraints matter?


    You can apply constraints in any order.

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  9. Can I use mates to temporarily position parts?


    In the Mate PropertyManager, under Options, select Use for positioning only. Components move to the position defined by the mate, but a mate is not added to the FeatureManager design tree. You can move the component away from its position by dragging it or adding another mate to it.

    This option avoids potential mate errors because mates are not applied to the model.

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Answers: Changing, Deleting, or Suppressing Mates

  1. How do I change a mate?
    1. Expand the Mates folder in the FeatureManager design tree.
    2. Right-click one or more mates, and click Edit Feature.
    3. Edit the options in the PropertyManager, then click .

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  2. Can I delete or suppress a mate?


    In the FeatureManager design tree, right-click a mate in the Mates folder and click Delete or Suppress.

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Answers: Mate Error Symbols

  1. My assembly has many yellow errors but my assembly looks fine. Why?

    Yellow usually indicates redundant distance mates only if no red errors exist. Fixed components can cause yellow errors. Diagnose the problem using MateXpert and delete the redundant mates.

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  2. What's the difference between red and yellow errors?

    Red = The mate is being violated. The parts are not in the positions specified by the mate. Another cause could be that the mate is dangling because one of the entities (face, edge, plane, etc.) is no longer in the model. Investigate red errors first.

    Yellow = The mate is satisfied, but another mate (usually red) is trying to move the parts in a way that would violate this mate. Another cause could be that this is a distance mate that is redundant to other mates in the assembly.


    The left and right components are fixed. The blue component floats. A coincident mate (Coincident1) is between the gray and blue blocks.

    When you add another coincident mate (Coincident2) between the blue and orange blocks:

    Coincident2 displays a red mate error because the parts cannot move as this mate requires.

    Coincident1 displays a yellow mate error because the red mate error is trying to move the gray and blue components and violate Coincident1.

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  3. What's the difference between the (+) and (?) prefixes to components in the FeatureManager design tree?

    (+) = over defined

    Conflicting or redundant over defining mates exist. Delete or edit the mate causing the problem. The best practice is to fix over defined mates when they occur.

    (?) = not solved

    SOLIDWORKS cannot solve the mate. Consider deleting mates, moving components closer to the solution, adding more mates, or changing the mate scheme.

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Answers: Mate Errors

  1. An error message appeared after I added a mate. How do I fix mate errors?

    The fix depends on the type of error. Use Search or look in the Mates section of the Table of Contents to find help topics about specific types of mate errors. Information about tools (such as MateXpert, mate callouts, Auto Repair , and View Mate Errors) is available. These topics help to identify and resolve mating problems.

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  2. The mate or mate icon I want to add is not available. Why?

    Only the mates that apply to the current selections are available. For example, you cannot make a concentric mate to a planar face.

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  3. I have a redundant mate. How do I know what mate it is redundant with?

    Use MateXpert to identify redundant mates.

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  4. Can I purge redundant mates?


    You cannot purge all redundant mates. Use MateXpert to identify redundant mates.

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  5. My mating angle flips direction. Can I stop this from happening?

    Verify the mate setup to make sure that it correctly defines your design intent. Use Search or look in the Mates section of the Table of Contents to find help on creating mates. If the problem persists, report it to technical support.

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  6. There are mate problems when mirroring. What do I do?

    Use the Mirror Component PropertyManager to create mirrored assembly components that preserve mates between components. The MirrorComponent feature holds the mirrored components in position relative to the seed components with respect to the mirror plane. No other mates are required to constrain the mirrored components.

    If you want to apply different mates to the mirrored components, right-click the MirrorComponent feature and click Dissolve Mirrored Component Feature. Then you can move and rotate the components and apply mates to them.

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