3d
If you edit shape of your profile and wall will be cuted like that shape.
To edit your profile go to Complex profiles - Profile manager
REad about this...you will need it A LOT
It this case we use profile to cut wall...but you can use profiles to get different shapes and you can use them with WALL, Beam and culumn
I hope that you will be able to folow this steps and i hope that this helps you.
OFC this is stupid and archicad wall supose to be able to strech and edit just like archicad slab tool. This all is workaround
im too tired and heading to my bed. GN . . .