// Point light values.
PointLight _ptLight = new PointLight();

public MyLights()
{
    for (int i = 0; i < nbrDirLights; i++)
    {
        _dirLight[i] = new DirectionalLight();
        _dirLight[i].Color = _dirLightColor[i];
        _dirLight[i].Direction = _dirVector[i];
    }

    _ptLight.Position = new Point3D(-3, -7, 10);
    _ptLight.Color = System.Windows.Media.Brushes.White.Color;
    _ptLight.Range = 15.0;
    _ptLight.ConstantAttenuation = 3.0;
}