The edge (fascia) cut is determined by the “Rafter Cut” parameter. When you create a new roof by default, the rafter cut will be “Plumb Cut”. Ie, vertical and no trim for a soffit.
Two Cut – Plumb is the next option for the Rafter Cut. This allows you to specify a fascia depth with will determine where your soffit is.
Two Cut – Square is the last option for Rafter Cut. Behaves like Two Cut – Plumb, but the fascia is square to the roof angle.
So this is starting to get close to what we want. By making the fascia dept equal or greater then the roof thickness, we are just about there.
The problem with the rafter cut parameter is it does not influence the upper fascia of a Skillion roof.
The only answer to fix how the fascia of the ridge looks it to actually use a Revit Roof Fascia. I created a profile to achieve this.
The profile is loaded into the project and the profile added to a roof fascia type.
This result will work perfectly for Sketch Design. Now for Design Development (DD) you may want to add to the above and insert your PFC. I’ve done this using an in-place roof family using a Solid Sweep using the “Pick Patch” and assigning a PFC profile. You can put the sweep on the fascia sub-category to help visibility.