internal IVector3D Normal()
{
IfcPolyLoop polyLoop = Bound as IfcPolyLoop;
if (polyLoop != null)
{
int numPts = polyLoop.Polygon.Count;
for (int i = 1; i < polyLoop.Polygon.Count; i++)
{
XbimPoint3D c = polyLoop.Polygon[i].XbimPoint3D();
XbimPoint3D p = polyLoop.Polygon[i - 1].XbimPoint3D();
XbimPoint3D n = polyLoop.Polygon[(i + 1 == numPts) ? 0 : i + 1].XbimPoint3D();
XbimVector3D left = c - p;
XbimVector3D right = n - c;
XbimVector3D cp = XbimVector3D.CrossProduct(left, right);
cp.Normalize();
if (!double.IsNaN(cp.X)) //happens if the three points are in a straigh line
{
if (!Orientation)
{
cp.Negate();
}
return(new IfcDirection(cp));
}
else if (i == polyLoop.Polygon.Count - 1)
{
// if its the last round of for look then just return the last cp
return(new IfcDirection(cp));
}
}
//srl removed the exception to stop invalid faces from causing a crash, an invalid normal is returned which can be checked for
return(new IfcDirection(0, 0, 0)); //return an invalid normal as the face is either a line or a point
//throw new Exception("IfcFaceBound:Normal has an Invalid face");
}
else
{
//srl removed the exception to stop invalid faces from causing a crash, an invalid normal is returned which can be checked for
return(new IfcDirection(0, 0, 0)); //return an invalid normal as the face is either a line or a point
}
// throw new Exception("IfcFaceBound:Normal has an undefined bound");
}