Control what component moves when mating

How can I control what component moves when mating? Is the only option
to have the component that is not to be moved mated to something to
begin with?

 

Mating normally starts with the first part inserted. There are several
options for positioning that part:

1. Drag it and drop it. It will automatically be fixed in whatever
orientation it was dropped.
2. Drag to the origin. In this case it will automatically line up with
the global xyz axes. When over the origin the mouse icon will change.
3. Drag and drop it and then set it to float and mate it to the global
planes or a reference plane of your choice or an envelope part or a
layout sketch.

Once the fist part is fixed you can drag in another part and mate it to
that part without the part moving.

If your assembly has a mechanism in it and the part move in unwanted
ways you have several choices:

1. Fix the moving part. Then drag the part to be mated close to it's
final position and mate it.
2. Turn off preview on the mate property manager and put all mates on
at once.
3. If you have a spaceball use it to manuever the part near to its
final position and mate it.

Just my 2 cents.
3.

 

I have found that which part moves depends on which one you select
first for the mate.
The first one being the one that does not move.

Does it still work that way? It was a simple way to control it but
have not tried lately, I usually always start with one part locked down
in the coordinate system.
~Alex