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← Shadow Summary - Interactive 3D Graphics

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Showing Revision 2 created 05/25/2016 by Udacity Robot.

  1. In this session we're going to take a look at shadows. This is a little
  2. environment i built and it's being lit by a directional light. When doing
  3. trivial graphics rendering, which I'm doing here, shadowing is typically not
  4. supported. For instance we can see that light leaks in under the little roof in
  5. the back of the scene. so let's lay a little shadowing. Now we can see that the
  6. scene is being properly shadowed. Parts of the environment that were previously
  7. incorrectly lit are now dark. This happens because we are now disabling light
  8. if there is something between the light source and the geometry. By rotating
  9. the light, we can also place the shadow where we want it. But there is still
  10. something wrong with the shadows. View live shadows are typically not as sharp
  11. as what we see here. Now we have enabled soft shadows. This looks much more
  12. realistic. Perfectly sharp shadows come from assuming the light sources
  13. infinite this small. In real life, light sources have size. And by taking it in
  14. consideration, we get a soft shadow border. This shadow border separates the
  15. shadow into two parts. We call the completely shadowed area the umbra. And the
  16. soft part with the gradient the penumbra. The penumbra happens in regions of
  17. the surface where the light source is being partially occluded. Also note how
  18. the penumbra has been small when the lit point is close to the occluder, and
  19. large when it's farther away. This wraps up the part about shadowing. Thanks
  20. for your attention