Additively manufactured core

A casting article for a gas turbine engine, comprising:

• a core having a core geometry including a first trunk and a second trunk that forms respective mainbody cooling passages separated by an internal rib of a cast gas turbine engine part and a skin core that forms an internal cooling passage of the cast gas turbine engine part, the skin core extending from the first trunk and the second trunk;
• wherein the core includes multiple layers of a powdered material deposited onto one another, the multiple layers are joined to one another, and the multiple layers include at least a portion of a second layer of the powdered material that is melted to adhere the second layer to a first layer;
• wherein each of the first trunk and the skin core includes a respective vascular network established in a volume of the respective main body and internal cooling passages, the vascular network includes a plurality of spherical nodes and a plurality of elongated branches that extend between the plurality of nodes to establish a lattice structure, and the vascular network is a hollow vascular network structure having interconnected internal hollow passages extending inside of the plurality of nodes and the plurality of branches;
• wherein the skin core is dimensioned to follow a contour of a shell that establishes an external wall of the cast gas turbine engine part;
• and
• wherein the skin core interconnects the first trunk and the second trunk such that the internal cooling passage extends between to interconnect the mainbody cooling passages.