title: Proper way to illuminate a 2D surface in 3D space?
body: <p><strong>EDIT:</strong> I've solved the issue below the tilde line -- the missing chunks -- by fixing an elementary error in my for-loop dealing with calculating face normals. I now have a new problem though: strange, unwanted shadows on the surface itself. Some areas appear darker than others... See the next picture for the current issue. </p>
  
  <p>I have an omni light added to my scene's root node as well as a directional light added in the same manner. For some reason I can't seem to light the underbelly of the surface otherwise. Notice the strange shadow on the inside of the concave surface (it's more pronounced when I remove the subdivision effect as I have done here) --> </p>
  
  <p><a href="https://i.stack.imgur.com/A1GSF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/A1GSF.png" alt="enter image description here"></a></p>
  
  <p>Here is the surface from above -- notice how some areas seem strangely darker. </p>
  
  <p>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</p>
  
  <p>This is a concave surface. </p>
  
  <p><a href="https://i.stack.imgur.com/Hq1A4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Hq1A4.png" alt="enter image description here"></a>                                           </p>
  
  <p>I have these smooth, curved planes in 3D space. Right now, they look rather cartoonish -- I would like to utilize some form of lighting to make them look more "3D-ish." </p>
  
  <p>I have tried various combinations of ambient lighting, omni lighting, and default lighting, but nothing seems to work right. I get something quite strange when I apply something like a basic omni light --</p>
  
  <p><a href="https://i.stack.imgur.com/R7Bhq.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/R7Bhq.png" alt="enter image description here"></a></p>
  
  <p>Here is another look at a better angle using omni lighting. Looks like someone took a bite out of it -- </p>
  
  <p><a href="https://i.stack.imgur.com/y0p9b.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/y0p9b.png" alt="enter image description here"></a></p>
  
  <p>Am I overlooking a specific type of light or lighting strategy? </p>
  
  <p>I'd like to avoid used baked lighting, because the scene is rather simple. Thanks.</p>
  
  <p>I'll outline my steps for the bold. </p>
  
  <p>1: I specify the vertices for each of the four faces of a pyramid-like shape. Like this (apologies for my lack of artistic ability) --></p>
  
  <p><a href="https://i.stack.imgur.com/B6KTJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/B6KTJ.png" alt="enter image description here"></a> </p>
  
  <p>2: I specify the indices for the face, i.e., [0,1,2, 0,2,3, etc.]</p>
  
  <ol start="3">
  <li><p>I create a dictionary mapping each vertex to the sum of that vertex's adjacent, normalized face normals.</p></li>
  <li><p>I append each of these summed up normalized per-vertex normals to a vector.</p></li>
  <li><p>I combine the vertices, indices, and vector of normals to create an SCN Geometry. </p></li>
  <li><p>To get the rounded look, I increase the subdivision count.</p></li>
  <li><p>Pray that it works. </p></li>
  </ol>
  
  <p>I'm new to the 3D world, so I could be way out in left field and not even know it. </p>