In the assembly window, select a part for which you want to capture relationships.
Choose Home tab→Relate group→Capture Fit 
.
In the Capture Fit dialog box, use the Add and Remove buttons to specify which relationships you want to capture, and then click OK.
Tip:
You can also select the part you want to use in PathFinder.
When you use the Capture Fit command, the relationships and faces used to position the part or subassembly the first time are stored so you can place the part using fewer steps later.
If you used the Insert option to position a part, the Capture Fit command will capture a mate and an axial align relationship, since these are the relationships that the Insert option actually places.
The Capture Fit command cannot capture angular, cam or center-plane relationships.
You can also capture relationships by setting the Automatically Capture Fit When Placing Parts option on the Options dialog box on the Place Part command bar.