If you are like me, I prefer to create corridors with seperate junctions (intersections) and side roads etc, rather than one monster corridor. Mainly due to having to only work with the corridor property panel. In 2011 this has been made easier with the interactive editing.
So I use a blank assembly to force gaps, i.e. an assembly with no subassemblies applied.
However you don't always change everything.
So what I am going to share is a simple technique to create one surface from a number of corridors.
The example is from the airport I mocked up for the Farnborough airshow last month.
In red is the main corridor surface and green the seperate junction (intersection) surface
So the corridor surface will actually span the gap of the intersection.
(You do not need to delete these triangles)
Create a new surface and paste in the main corridor first
Then paste in the junction (intersection) corridor surface
You will find that the two surfaces merge together perfectly.
So you see here that order of the surfaces being pasted together is important to which surface get priority.
(You can change this in the surface properties which is really cool)
Here we have the final surface merged
So here is the final result of all the corridor surfaces pasted below and of course all dynamic!