David Gaskill, a CAD designer, sent in an Autodesk Inventor tip about applying constraints to an assembly.
"Have you ever had components in an assembly placed at the correct location without constraints, and wanted to add a constraint without having the part move? There is a way to get the result you want without measuring the distance between parts. Activate the Predict Offset and Orientation button on the Place Constraint dialog box. The part will stay put, add a mate or flush constraint, and predict the offset, thus leaving the part in its original location; now it’s constrained.
"Warning — this does not work well with Insert. Also, don’t forget to turn off the command when you are done."
Notes from Cadalyst Tip Reviewer Brian Benton: This tip will help you to constrain your assemblies. Constraining your parts properly in Inventor (or any design program) is crucial. If you don’t follow the correct steps and procedures, then neither will your design.