public byte Shininess {get; set;}

{
  var sr = MapView.Active.Map.SpatialReference;

  var extent = MapView.Active.Extent;
  var center = extent.Center;
  var centerZ = MapPointBuilderEx.CreateMapPoint(center.X, center.Y, 500, sr);

  // cube
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Cube, centerZ, 200, sr);
  // tetrahedron
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Tetrahedron, centerZ, 200, sr);
  // diamond
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Diamond, centerZ, 200, sr);
  // hexagon
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Hexagon, centerZ, 200, sr);

  // sphere frame
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.SphereFrame, centerZ, 200, 0.8, sr);
  // sphere
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Sphere, centerZ, 200, 0.8, sr);
  // cylinder
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Cylinder, centerZ, 200, 0.8, sr);
  // cone
  multipatch = ArcGIS.Core.Geometry.MultipatchBuilderEx.CreateMultipatch(MultipatchConstructType.Cone, centerZ, 200, 0.8, sr);

  // use the builder to add materials or textures
  // create the multipatchBuilderEx object
  var builder = new ArcGIS.Core.Geometry.MultipatchBuilderEx(multipatch);
  //   - create a cone with a material
  builder = new MultipatchBuilderEx(MultipatchConstructType.Cone, centerZ, 200, 0.8, sr);

  BasicMaterial faceMaterial = new BasicMaterial();
  faceMaterial.Color = System.Windows.Media.Color.FromRgb(255, 0, 0);
  faceMaterial.Shininess = 150;
  faceMaterial.TransparencyPercent = 50;
  faceMaterial.EdgeWidth = 20;

  foreach (var patch in builder.Patches)
    patch.Material = faceMaterial;

  multipatch = builder.ToGeometry() as Multipatch;
}

{
  // Create BasicMaterial with default values
  BasicMaterial material = new BasicMaterial();
  System.Windows.Media.Color color = material.Color;         // color = Colors.Black
  System.Windows.Media.Color edgeColor = material.EdgeColor; // edgeColor = Colors.Black
  int edgeWidth = material.EdgeWidth;                        // edgeWidth = 0
  int transparency = material.TransparencyPercent;           // transparency = 0
  int shininess = material.Shininess;                        // shininess = 0
  bool cullBackFace = material.IsCullBackFace;               // cullBackFace = false

  // Modify the properties
  material.Color = System.Windows.Media.Colors.Red;
  material.EdgeColor = System.Windows.Media.Colors.Blue;
  material.EdgeWidth = 10;
  material.TransparencyPercent = 50;
  material.Shininess = 25;
  material.IsCullBackFace = true;
}