With the advent of renovation in Archicad 15, the transition from existing conditions to new construction is much simpler. We still want to finalize and set aside the existing conditions before moving on.
Publish the existing conditions layouts using the 'PDF Existing' publisher set. The path is blank in the template, and you should set it to 1 Projects/[ProjectName]/4 Site & Existing.
Name it [Project Name] Existing Conditions [Date].
Save the 'Existing Somebody.PLN' file. (It's easy to forget to save before saving as. This results in lost work!)
Save as 'Somebody Addition.PLN'. Save it at the top of the project folder.
Leave the 'Existing Somebody.PLN' in the '4 Site & Existing Conditions' folder.
Change the renovation filter to '04 New Construction'. Or just apply one of the post-existing views. Change the Default Elements setting to New.
When switching to other viewpoints, watch that filter setting, it may try to backslide on you.
In Archicad 20, favorites are completely overhauled. Our addition template contains favorites for existing conditions as well as all the favorites offered in the new home template. The only difference for existing favorites is that they generally use the 'Existing Poche' building material. With renovation filters, what decides if an element is existing or new is the state of the Default Elements button in the Renovation palette. Renovation status is not part of favorites.
All you have to do when starting on new work is to stop using the X_ prefix favorites in the '! Existing Conditions' folder. (Tip: change the '!' to a 'Z' to force the folder to the end of the list.) Pay special attention to the building material of model tools. New elements should never use the Existing Poche building material.