The ill and ilp functions determine intersection points.

ill(p1,p2,p3,p4)

Determines the intersection point between two lines (p1,p2) and (p3,p4). All points are considered three-dimensional.

ilp(p1,p2,p3,p4,p5)

Determines the intersection point between a line (p1,p2) and a plane passing through three points (p3,p4,p5).