/// <summary>
 /// Do the tessellation and return the <see cref="MeshGeometry3D" />.
 /// </summary>
 /// <returns>
 /// A triangular mesh geometry.
 /// </returns>
 protected override MeshGeometry3D Tessellate()
 {
     var builder = new MeshBuilder(false, true);
     builder.AddTorus(this.TorusDiameter, this.TubeDiameter, this.ThetaDiv, this.PhiDiv);
     return builder.ToMesh();
 }