protected override void Draw(GameTime gameTime)
        {
            graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

            // Show camera position on-screen
            spriteBatch.Begin();
            string posText = String.Format("cameraPos: {0}x {1}y {2}z", cameraPosition.X, cameraPosition.Y, cameraPosition.Z);
            Vector2 fontOrigin = gameFont.MeasureString(posText);
            spriteBatch.DrawString(gameFont, posText, textPos, Color.Black, 0, fontOrigin, 0.8f, SpriteEffects.None, 0.5f);
            spriteBatch.End();

            // Copy any parent transforms.
            Matrix[] transforms = new Matrix[myModel.Bones.Count];
            myModel.CopyAbsoluteBoneTransformsTo(transforms);

            // Draw the model. A model can have multiple meshes, so loop.
            foreach (ModelMesh mesh in myModel.Meshes)
            {
                // This is where the mesh orientation is set, as well as our camera and projection.
                foreach (BasicEffect effect in mesh.Effects)
                {
                    effect.EnableDefaultLighting();
                    effect.World = transforms[mesh.ParentBone.Index] * Matrix.CreateRotationX(modelXRotation) * Matrix.CreateRotationY(modelYRotation)
                        * Matrix.CreateTranslation(modelPosition);
                    effect.View = Matrix.CreateLookAt(cameraPosition, Vector3.Zero, Vector3.Up);
                    effect.Projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), aspectRatio, 1.0f, 100000.0f);
                }
                // Draw the mesh, using the effects set above.
                mesh.Draw();
            }

            base.Draw(gameTime);
        }