

Your not telling us something because this just doesn't happen. Any suggestions on how to improve the speed or if I am doing anything wrong which is affecting the speed will be hugely appreciated.

Everything cut by the pink line (like in the image below) will display in thick lines.

although you could get VRay and make some lovely simple rederings to hide the lines from the models. This is more pronounced if the structural slab is in the structure model only. Underlay Visibility Issue in Linked Models Revit. If your roof planes are not displayed on the floor level the dormer will be created on, navigate to the floor level where they are currently displayed, select the roof plane(s), and click the Display on Floor Above or Display on Floor Below edit tool(s). Revit hide second floor Within the primary range there are 3 planes: Top, Cut plane and Bottom.
