In a support shell assembly for supporting and splinting legs comprising a left and a right leg shell and a sole element that is fastened to the leg shells, wherein the leg shells and the sole element have fastening means for receiving a tensioning element, arranged within the support shell assembly (5) there is at least one layer of a 3D textile (1) comprising at least two layers of a textile material which are held at a defined and pressure-resilient distance from one another by flexible threads (FIG. 3).