Graphic overrides are a new feature of Archicad 20. They allow you to choose elements by criteria, and change their appearance attributes. The changes are grouped into combinations which can be saved with views.
Here's how to use Archicad: Build a model, and try to create all the documentation while doing the least amount of non-modeling. If you find yourself drawing something that you have already modeled, it must be because the thing can't be made to present itself in the appropriate way for your documentation. Archicad has always offered methods to help with this. A door can have a complex plan symbol, a simple symbol, or just an opening; it can have a schedule marker or not; or it can be hidden entirely. The same one door appears in 3D and in a schedule. One door, many appearances in documentation. This is unity.
Graphic overrides greatly expand the variety of ways that a single element can be presented. This means it is less likely that you will need to 'draw' an element you have modeled in order to get it to appear correctly in your documentation.
This feature gets at the heart of what Archicad is all about. It will definitely change a lot of working and documentation methods. If it doesn't, you are probably using Archicad wrong.
Since this is a major feature, it is impossible at this early stage to predict everything that will change. But I am getting a sense of what the categories of changes might be.
These aren't optional. Graphisoft has removed all the fill-related options from MVO and replaced them with graphic overrides. This is now how you turn cover fills off, or cut fills solid black.
When you migrate an Archicad 19 project, the is an override rule created for every possible fill setting from the old MVO. We only ended up using about six of them.
In the floor plan, we show counters as solid and overhead beams as dashed. In the reflected ceiling plan, the counters are dashed while the beams are solid. Previously, the counter had to be drawn over with lines in the RCP. Now we can simply show the counter itself with a dashed line, and the beam itself with a solid line. One counter, one beam, no drawing. Our RCP standards will be getting a big rewrite.
We have favorites for furniture. The favorites have the correct plan pen, which is lighter that the pen for other objects such as plumbing fixtures. The trouble is, some furniture ends up with the right pen from the favorite, and some ends up with a heavier pen because I forgot to use the favorite and copied a toilet before turning it into a sofa. You can use graphic overrides to force all the furniture (Criteria: Objects on the layer F Furniture) to be the correct pen, regardless of the setting of the objects themselves. Further: That furniture pen is very thin but black. If we want to use a gray line instead, we would change the rule, rather than all the objects' settings.
I can also arrange that I never have to see pen -1 ever again.
I got rid of these pen sets:
• All Pens Black
• White poché for wall sections
• Lighter doors and windows for electrical plans
I replaced them with graphic override rules to:
• Turn lines of all elements to the color (only! Not weight.) of pen 1.
• Turn the background pen of all cut fills to 91.
• Turn all the doors and windows to pen 161.
Now that these pens tweaks are handled by graphic overrides, the respective drawings can use the standard output pen set. N.B., not all pen sets are hacks!
In conjunction with element classification and the new Archicad properties, you can show which walls are bearing walls, or which have this or that fire rating. Judging by the reference guide and the feature videos, Graphisoft imagines this to be the primary application of graphic overrides.
Graphic overrides affect elements, not parts of elements, and not attributes. The criteria selector for graphic override rules is nearly identical to the one for find & select. If you can't grab something with find & select, you probably can't apply overrides to it.
So, you can't override the outline of a roof, while not overriding the cut portion. This is a puzzling limitation, because you can control overrides by fill category. (Hilariously, you can give a line element the 'cut' line category, and override that. You can override fake cut lines but not real ones.)
You can't override only the top surface of a slab, e.g., while leaving the other faces alone.
You also can't override the framing portion of a wall composite, while not overriding the brick portion. You can, however, override a concrete and stone veneer composite so that it appears to be all concrete.
Another disappointment is that cleanup between matching section fills seems to take place before the overrides are applied. With the override in effect, the fills will appear different, but the line between them is not drawn.
I'm sure there are other limitations to discover, but graphic overrides are a big step forward in unifying the model and documentation.