sArc:

sArc is an arc that lies on a surf. It can be created on the sNodes of the same surf or nodes/sNodes used in the boundry arcs of the surf. Like arcs, sArcs also have a control point that lies on the same surf. You can control the curvature of the sArc by changing the location of its control point coordinates CPS and CPT. If 'Edge smooth' is selected, it will modify the surface normals of adjacent surfs/sSurfs so that it looks smooth.