Floor
X => In the middle of the mesh, at the bottom.
L = B (after the last update*)
H = "i use 10"
Wall
X => At the base of the mesh, in the middle of the length and width.
L = Floor [L] (indicated)
Ramp
X => the same point as the floor, [place it over the floor].
B = L = Floor [L] (indicated)
H = Wall[H] (indicated)
Notations
X. => Mesh Pivot
H => Mesh Height
B => Mesh Width
L => Mesh Length
Here you have the necessary details in case you want to add your own building parts.
it must have the respective pivot of its category.
to have similar dimensions between them.