I'm working in Revit MEP 2012. When I have a view's discipline set to Coordination, linked architecture, lighting, and other non-Mechanical elements show as boldly as my duct, piping and mechanical equipment.
When I switch the view's discipline to Mechanical, all non-mechanical items (walls, lights, generic models, etc) fade into the background (half-tone) as desired, but switch to a dashed line. This happens regardless of Phase (Existing, demolition or new work). Switching the elements' linetypes in Visibility/Graphics overrides to Solid doesn't fix the problem.
Where do I edit the graphics displays of non-mechanical elements in Mechanical views, non-electrical elements in Electrical views, etc?
You cannot edit the discipline-based visibility alteration, they're set in stone. However, if your out-of-discipline elements are changing to a dashed line, that is a separate issue. Perhaps they are hidden? Could you provide a little more info on the situation, perhaps some images of the View and the View's Properties?
This could potentially also be a view range issue with the beyond linestyle being set to dashed. If the View Depth is set below the bottom cut plane then the beyond linestyle domes into play
It is connected with Underlay. When you change Underlay settings, you change the background lines properties for disciplines like MEP. In my opinion it is a very bad system, because it can interfere between work of architect and MEP designer. If you want to avoid that, you need to have disciplines linked to your central file.