Here is an old one but a good one.
If you want a double brick wall with cavity to join on ends and intersecting walls to create a continious cavity automatically here is how.
1.Duplicate or create a normal double brick wall (image1)
2.Now you have to delete the "function" from the material that is outside
the core boundry. (image2)
There is a trick here Revit will not let you just select and delete the whole
function line. You have to select just the function type ie. "finish" and delete
and leave the number in brackets ie.(4) (image3) Then press OK then the function will
Set wrapping at ends to "exterior" all done.