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Planar mates not working

joshua_foxworthjoshua_foxworth Member, Developers Posts: 19
edited July 2017 in Community Support
So, I had an assembly built out and working fine. I made a few changes that blew up the assembly and now, nothing seems to be working. Trying to do a simple planar mate results in nonsensical mates to items not even clicked. 

In the image below, the bottom surface of the fitting is affixed to the square insert in the ring using a planar mate. Obviously, those two planes are not mated. The same happens for a fastened mate. Obviously, this does not function like the example (https://cad.onshape.com/help/Content/mate-planar.htm).

Additionally, attempting to set mate connectors on those faces results in the connectors being placed at the center of the ring. Literally, when I click on the face of the extrude, the mate appears at the center.

My guess is that the fitting is connecting to the center for the same reason that the mate connected, but that reason eludes me - especially when this worked yesterday.

What is wrong here?


Best Answer


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    NeilCookeNeilCooke Moderator, Onshape Employees Posts: 5,386
    I had a look and could not see what you were struggling with? You should only use planar mate if something needs to move on a plane. If something is fixed use fasten. If something rotates use revolute or cylindrical (like you have). There should be no need to create mate connectors on this geometry just "wake them up" when mating. A mate connector will go to the centre of a cylindrical object always. 

    If you're still struggling can you explain what you are trying to achieve?
    Senior Director, Technical Services, EMEAI
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    joshua_foxworthjoshua_foxworth Member, Developers Posts: 19
    I am trying to mate the back surface of the fitting to the surface of one of the square insets seen at the far side of the ring above.

    I eventually "solved" the problem by mating one of the bolts holes in the fitting to one of the bolt holes in the ring and then using the limiting factors to position the fitting accordingly. However, I do not believe that this is appropriate as it will cause problems when dimensions change.

    I just want to mate the fitting surface to where it will be mounted.
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    NeilCookeNeilCooke Moderator, Onshape Employees Posts: 5,386
    Considering the plate will be fastened to the ring with bolts, doesn't it make more sense to fasten those features together?

    Sometimes mates will fight each other to see who wins. If you reduce the conflicts (like using cylindrical instead of revolute if you can) you are less likely to run into issues.
    Senior Director, Technical Services, EMEAI
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    john_mcclaryjohn_mcclary Member, Developers Posts: 3,898 PRO
    If I am seeing this correctly, the square area "Inside" the ring is flat. If that is true, that a simple fastened mate would have been all you need.

    Pro tip: move the part close to it's final position before adding a mate. Rotation can be achieved by selecting the part and using the manipulator tool.
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    joshua_foxworthjoshua_foxworth Member, Developers Posts: 19
    Appreciate the help. It appears that I didn't really grasp what a fastened mate was and how it was used. I am still confused as to why the planar mate failed, but the fastened mates was definitively the way to go. 
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