A reference marker is a special object that can intelligently refer to viewpoints within the project or drawings placed on layouts. They also create viewpoints, which is a strange kind of double duty. Then you can also create viewpoints without markers... it's not intuitive overall. For most cases, you can think of a viewpoint as an application window. Sections, elevations, interior elevations, details, and worksheets are all viewpoints. So are schedules and even stories, but they are not related to the marker discussion in the same way. Everything in here applies equally to sections, elevations, and details.
A source marker creates a viewpoint. It is the viewpoint, in a manner of speaking. If you delete a source marker, you delete the viewpoint. If you copy a source marker, a new, additional viewpoint is created.
A linked marker is more like an object, though still a special one. When you place a linked marker, no viewpoint is created; the marker points to something. Any number of linked markers can point to a particular viewpoint or drawing. They are just pointers, and they can be created or destroyed without affecting anything else.
Both source and linked markers can refer to drawings.
You can have a viewpoint with no marker. Such a viewpoint is independent. You will very often have independent details. At this time all of our worksheets are independent. You can even have independent sections and elevations, but I don't see any advantage to these. Interior elevations can't be independent.
When you get ready to place a marker, whether to draw a new section or refer to an existing detail, you will see these choices in the info box:
When you select a marker, the options look like this:
You can turn a source marker into a linked marker and vice versa, but don't. It's complicated, potentially destructive, and I'm pretty sure it's silly. Treat your viewpoints as 'real' things, and use linked markers to point to drawings in any way you like.
In practice, a linked marker should always refer to a drawing. It makes for a smoother workflow if you place the drawing in the layout before placing linked markers.
When you choose to refer to the drawing rather than the viewpoint, you have three choices.
• The selected drawing lets you choose the drawing manually from the layout tree.
• The first placed drawing of the viewpoint means you don't have to choose the drawing. The marker will find the first drawing of that viewpoint in the set and refer to that. You can choose this option before the drawing is placed. If you go this route, make sure the first drawing is the only drawing, or you are sure the first one is the one you want. N.B.: In our layout tree, the schematics sub-book comes before the CDs, so this 'first' thing will always use a schematic elevation instead of the same elevation in the CDs.
• Similarly, the first drawing of the selected view lets you name a view in advance of placing any drawing. When the drawing is placed in due time, the marker will refer to it. This 'first' method is safer, because 'view' is more specific than 'viewpoint'. For example, the schematics and CDs use different views.
With a source marker, you can only choose a viewpoint, view, or drawing associated with the marker's viewpoint. A linked marker can point to anything.
When you have a source marker selected and you strike delete, you will get a warning to the effect that deleting a source marker will also delete that marker's viewpoint, unless you choose to keep it as independent. If you confirm that you want to delete the viewpoint along with the marker, you be warned again, to the effect that deleting sections (e.g.) is not undoable. This second warning is as old as the section tool itself, and you know what it means.
If you delete a viewpoint from the Project Map, you will only get the warning about undoability. When a viewpoint is deleted in this way, its source marker and any linked markers are automatically deleted.
When you delete a linked marker, you don't get a warning, because nothing important or non-undoable is happening.