myRenderer->SetDisplayPoint (theDisplayPnt.X(), theDisplayPnt.Y(), 0.0);
myRenderer->DisplayToWorld();
vtkFloatingPointType* const aCoords = myRenderer->GetWorldPoint();
double* const aCoords = myRenderer->GetWorldPoint();
if (aCoords[3] == 0.0) // Point at infinity in homogeneous coordinates
{
return false;