There used to be a way of automatically indicating stories above, or roofs, etc, with dotted (hidden) lines. Stories below could be shown in solid lines. AC26 has a legacy setting option which is supposed to do this, but I can't get it to work. What and where are the current version equivalents. Surely, we don't need to use the legacy feature to achieve something as fundamental as this?
What works for me: the element (Slab, Roof) is set to Floor Plan Display > Show on Stories > Home & One Story Down. Under Preferences > Legacy the Below Home Story Line Type is set to dashed. Even though this is in the Legacy panel, it cannot be turned on/off like the other options; I do not consider it a legacy feature.
There is an old trick where on a layout you can place one view above another. Set up the below or above with a GO to get the linetypes and colours you want. You can trace ref these views too. View on top needs to have a transparent background