Custom features used
Copy and Split Mesh
Mesh Projected Curve
Mesh Intersection Curve
Spline on Mesh
https://cad.onshape.com/documents/53ca0ca4ee0dce4a4c544698/w/1cded8bc47e636460ba13f02/e/c3d5102cef50179684e11354
Keep Face
https://cad.onshape.com/documents/0ceec4d8948c2a14ff2db75c/v/7f1717e8be929a229d5dc89d/e/40e0f4355973a4e61447cf24
Freeform Spline
https://cad.onshape.com/documents/cd51f29c6937305f86a9df95/v/ad52f46ed999aedd596222e1/e/27d79de4b4e2ddcdba150ebe
3D Points
https://cad.onshape.com/documents/309e817bcaf616677a834985/v/06e6a30bd1d0ee6c87d2d763/e/b28795ae9aec5a245cccb936
Cap Surface
https://cad.onshape.com/documents/c9dbd91fc42dd492cc5509e7/v/60d31c58d211cee400ecd1f5/e/123acbaf149089f23dc9756f