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# Behavior of Mates with Offset and Rotation

Member Posts: 193 PRO
Did the mating behavior recently change in the way it applies offsets and rotations?  I thought I used to have to rotate to the correct orientation using the "Reorient secondary axis" button before I applied an offset. Now, it seems like the coordinate system is independent of the angle, so the offset can be applied before the rotation.  Did this change recently?  I thought I remembered parts orbiting each other if I hit the "Reorient secondary axis" button with an offset applied.

I have never fully understood the theory behind how mates function.  It would be great if there were some simple videos to explain the details of how the inputs to mates affect the result.  I get by fine by pressing buttons until I get what I want, but I would like to be more deliberate with my selections and button pushes.
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Member Posts: 1,607 PRO
I don't think anything changed recently... I'm guessing what you are seeing is related to the selection order as explained below

A couple key things you need to know in order to predict what is going to happen:

Order matters: offsets and rotations are based on the first selected mate connector axes. Offsets are applied TO the first selected mate connector, however this can lead to unexpected offset direction if that part is fixed: for example if you select a fixed part first and apply an offset in the +x direction, it will end up moving the “free” part (the one you are mating) in the -x direction.

For most predictable results, select the part to be mated first and the part you are mating to second (i.e. the fixed part second). You can adjust the order in the dialogue after the fact so if you get unexpected results try reordering the mate connectors.

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Member Posts: 193 PRO

Order matters: offsets and rotations are based on the first selected mate connector axes. Offsets are applied TO the first selected mate connector

For most predictable results, select the part to be mated first and the part you are mating to second (i.e. the fixed part second).

I will have to keep this in mind.  I think this might be the bit I was missing.  Thanks for the tip.