Single-family house with staggered floor, southwest location in Bonn

It is not a cube, but otherwise more like a "linear body" with all exterior walls.

No no, only parallel.

I count 9 exterior corners.

A building has three dimensions.

I will also have the architect explain it to me.

That he will be able to deliver eloquently.

Well, maybe someone else can try to really explain to me why having so many red lines is so bad. Otherwise, we'll just keep talking past each other :)

Few sections (few red lines) = Few complex (structural & construction) details = Low costs Many sections (many red lines) = Many complex (structural, construction) details = High costs

Few cuts (few red lines) = Few complex (static & structural) details = Low costs Many cuts (many red lines) = Many complex (static, structural) details = High costs

That's roughly how I understood it too, but what exactly it reflects is still not clear to me. The design has more corners, etc., but what exactly a cut shows me is still completely unclear.

but what exactly a section shows me is still completely unclear to me

The same as a floor plan, only in a different dimension. A floor plan is a section from the bird’s-eye view, a section is basically a view like an X-ray image and not on the facade level, but somewhere “behind” it. Where exactly is then indicated by the (here red) lines in the floor plan. These cross-sections are sensibly placed only through a few “interesting” details, e.g. so that the stair rise is captured. Floor plans are made one per floor. If more sections are made in the other dimensions than just one lengthwise and one crosswise, this is an indication of tricky points and/or otherwise difficult to understand building bodies.

Where do you start and where do you stop...

First of all, I liked the hand drawings and first drafts significantly better than the current design.

If I counted correctly, it should be 243 sqm of living space on the ground floor and upper floor. Considering that there are so many square meters, it doesn’t feel spacious at all. One corner follows the next.

There is no proper space for the wardrobe on the ground floor; with four people, that adds up.
The slanted wall/door to the kitchen is a disaster and basically only serves as an emergency solution and is not what you expect from an architect.
The living room is a ballroom but doesn’t feel like one. Our living/dining room has 52 sqm and that is already very generous.
Could it be that there is no window in the ground floor bathroom? I would definitely install one.

The upper floor is a disaster, way too convoluted. We have a few more square meters upstairs than you, but a separate parents’ and children’s area. I would never want my bedroom next to a child’s room.
I would seriously reconsider the trapped bathroom upstairs, especially if you get up at different times in the morning.

Laundry has already been mentioned. I would install a laundry chute via the utility rooms, with a slot for disposal to the hallway on both the upper and ground floor. My wife initially didn’t want that; today she won’t want to miss it...

You mentioned construction costs including additional costs of 900,000 EURO; I think it will be significantly more. The house is a Porsche from a structural engineering perspective...
We have 20 sqm less living space than you, built in 2017 and also not an easy structural setup. We are now seven-figure, house including garden facilities, and we don’t have a pool. Keep in mind that we provided a lot of the work ourselves and bought materials at purchase prices in some trades.

I would almost say, back to start.

Question, why does the current plan differ so much from the hand-drawn one?