The origin mate saves you two mates every time you use it.
It’s a feature that you don’t easily run in to.
Someone else really has to point it out to you.
Today that someone else is me.
Mating the first part of an assembly: old method
I am very detail oriented when I am setting up 3D models. That is why the part/assembly at the top of my assembly tree is always the main component. It can for example be the frame of my machine, or the surroundings where the machine will be installed.
When this component is inserted, I immediately remove the fixed position property (right click > Float) because it looks like a lazy person just left it there. Then I add three mates: Front Plane to Front Plane, Top Plane to Top Plane and Right Plane to Right Plane.
It is a chore to do this every time, but there is no other option. Or is there?
Introducing: the Coincident Origin mate
There is a hidden option when you create a Coincident mate and it only reveals itself when you select two origins. It doesn’t even work with regular points.
You can see two versions of the mate window below. The version on the left is the one you have seen a gazillion times. The one on the right shows the hidden option.
As you can see, there is one more checkbox available.
You can make the two points coincident just like you can do with any other two points, or you can align all three axes and make all three planes of the two components coincident to each other.
Keeping that checkbox checked will save you from adding two extra mates. Who can say no to that?
It works for any model
The previous example showed how you can use this feature for adding the first part to an assembly.
The origin mate works for any combination of models though.
Mating two origins is great when you design parts with a common origin. That way you can get ten parts (or assemblies) fully constrained with only ten mates.
Is it slower than three normal mates?
No, there is no difference in performance between three coincident mates and an origin mate. Under water they are exactly the same, so there is no reason not to use the origin mate!