Architectural objects not appearing in your MEP model?

If you link in an architectural model and notice some elements are missing, first check your Visibility/Graphics and View Range settings. If those setting are correct and the elements still aren't showing up, there is a good chance it is a workset issue. When worksets are created, there is an option to make them "visible by default in all views”. If an architect creates a workset and unchecks this option, any object he or she places on that workset will not appear when the model is linked into a Revit MEP model (when the MEP views are set to "By Host View"). If the architect did this unintentionally, he or she will need to create a new workset with the “visible by default in all views” option checked, transfer the objects over to the new workset, and send you the updated Revit file. Same goes for us MEP guys. If we create a workset not visible in all views and place objects on that workset, those objects will not be visible when an architect links our model into theirs (when the architect's views are set to "By Host View"). Keep in mind that once a workset is created, there is no way to change that visibility setting.