Creates a polygon out of one or more contours of 3D (point, texture-coord) pairs, given by c.
The 3D points are projected onto a plane (given by p), afterwards the resulting 2D contours are triangulated, and finally the triangles are mapped back into 3D again.
p is also used for deciding which sides of the triangles are the front sides, and for defining a parametrization of the polygon plane (can be used as 2D texture coordinates).
c is a typeless node to which the contours (lists of 3D (point, texture-coord) pairs) are connected. p is a typeless node to which 3 points A, B, C are connected. A is used as the origin of the polygon plane, B-A and C-A as the two basis vectors, and the orientation of the cross product (B-A) x (C-A) determines which side of the plane is the front side.
The following variations of this keyword exist (some of them define the same internal structures, and are only defined to allow consistent naming conventions):