The layout of the bird's mouth and overhang for a hip jack rafter is made or secured from the ______.

The layout of the bird's mouth and overhang for a hip jack rafter is primarily derived from the common rafter pattern. This is because hip jack rafters, which support the roofing structure on a hip roof, need to match the angle and positioning of the common rafters to ensure a proper fit and structural integrity.

The common rafter pattern provides the necessary dimensions, including the rise and run, which are essential for establishing the correct angles and measurements for the bird's mouth cut, which allows the rafter to sit flush on the top plate of the wall. Additionally, the overhang measurement is also taken from the common rafters, ensuring that all elements of the roofing system are cohesive and uniform.

While hip rafter measurements, diagonal cuts, and the main beam may play roles in the overall construction of the roof system, they do not directly provide the specifics needed for the bird's mouth and overhang layout like the common rafter pattern does. Hence, it is vital to reference the common rafter pattern for accurate construction.