MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using HelixToolkit.Wpf;

namespace _3DRender
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {

        public MainWindow(string path)
        {
            InitializeComponent();
            ModelVisual3D model = new ModelVisual3D();
            model.Content = Display3d(path);
            viewPort3d.Children.Add(model);
        }
        
        private Model3D Display3d(string path)
        {
            Model3D tmodel = null;
            try
            {
                //Adding a gesture here
                viewPort3d.RotateGesture = new MouseGesture(MouseAction.LeftClick);

                //Import 3D model file
                ModelImporter import = new ModelImporter();

                //Load the 3D model file
                tmodel= import.Load(path);
            }
            catch (Exception e)
            {
                // Handle exception in case can not file 3D model
                MessageBox.Show("Exception Error : " + e.StackTrace);
            }
            return tmodel;
        }
    }
}