cut a mesh by a hyperplane and remove parts above/below that plane
cutMeshPlane(mesh, v1, v2 = NULL, v3 = NULL, normal = NULL, keep.upper = TRUE)
mesh with part above/below hyperplane removed
triangular mesh of class "mesh3d"
numeric vector of length=3 specifying a point on the separating plane
numeric vector of length=3 specifying a point on the separating plane
numeric vector of length=3 specifying a point on the separating plane
plane normal (overrides specification by v2 and v3)
logical specify whether the points above or below the plane are should be kept
see cutSpace
for more details.