public static Surface ExtractSurface(Autodesk.Revit.DB.PlanarFace face, IEnumerable<PolyCurve> edgeLoops)
{
edgeLoops = edgeLoops.ToList();
var x = face.get_Vector(0).ToVector(false);
var y = face.get_Vector(1).ToVector(false);
// Construct planar surface larger than the biggest edge loop
var or = edgeLoops.First().StartPoint; // don't use origin provided by revit, could be anywhere
var maxLength = edgeLoops.Max(pc => pc.Length);
var bigx = x.Scale(maxLength * 2);
var bigy = y.Scale(maxLength * 2);
return Surface.ByPerimeterPoints(new[] { or.Subtract(bigx).Subtract(bigy),
or.Add(bigx).Subtract(bigy),
or.Add(bigx).Add(bigy),
or.Subtract(bigx).Add(bigy) });
}