Ok, this took longer to make than I expected but here we go.
First I derived a side view of a few selected planes from your guesswork version and then continued to derive the corresponding floor plan for the cabinet projection from that. As you can see (though, you can even see that without going through all this trouble
) the front of the building foundation aligns with the front of the house box while in the back, the foundation extends beyond the house box.
If you would continue this reverse derivation for other planes, you would find that your roof does not fully cover the house box (while in the front it appears to overlap a bit, in the rear it would not extend long enough to hang over the rear wall probably would not even reach it).
Anyway, below I'm illustrating an "easy" (still requires thinking) way to do that kind of projection/construction on the basis of a floor plan and an elevation plan (which are easier to do for most people than to jump right into winging it all in imaginary 3D space).