Custom seams can be used to connect a main part(1) part that exists in a building object and that determines the position number for the assembly or cast unit and the direction of assembly or cast unit drawings
(1) Main part can be an assembly main part or a cast unit main part.
(2) input part that the user selects first when creating a component
(2) Connections and details always have a component main part.
to up to 30 secondary parts. They can also be used on one main part only. The seam is made along the length of the part. The following images show some examples of custom seams: