title: C# Interacting with ModelVisual3D objects in WPF
body: <p>Hey I am using a WPF 3D scene and successfully loaded a few .stl models into it.
  I am basicall using a method to select and deselect these objects, based on where my mouse in the windows is:</p>
  
  <pre><code> private void UIElement_OnMouseDown(object sender, MouseButtonEventArgs e)
          {
              var viewport = (HelixViewport3D)sender;
              var firstHit = viewport.Viewport.FindHits(e.GetPosition(viewport)).FirstOrDefault();
              if (firstHit != null)
              {
                  this.viewModel.Select(firstHit.Visual);
  
              }
              else
              {
                  this.viewModel.Select(null);
  
              }
          }
  </code></pre>
  
  <p>So I have the selected ModelVisual3D and could store it. However here is the main problem:</p>
  
  <p>My models are generated based on certain data and an associated .stl model.
  Basicall I import the .stl model and show it in my 3D scene, but the problem is I have no idea how connect my other data to the model.</p>
  
  <p>For example when I select the visual, I want to show another windows with information like: material, dimensions, company.</p>
  
  <p>But I can't figure out how to determine, which unique ModelVisual3D object is selected at the moment. There seem to be no properties I could use to my advantage doing something like:</p>
  
  <pre><code>ModelImporter tr = new ModelImporter();
              var model = tr.Load("C:\\Users\\...\\Pictures\\a.stl");
              ModelVisual3D test = new ModelVisual3D();
  
              test.Content = model;
  
  //Here I would like to save the id of my visual model to identify and
  //associate it with my other data later
  
              int myUniqueModelID=test.Properties.UNIQUEID
  </code></pre>