Dan Fergus Design > Student Resources > Syllabus > Lightsaber Rotoscope

GMD•200 Digital media 1

Exercise: Lightsaber Rotoscope

Rotoscopting was originally a technique for creating animations by tracing over live-action frame by frame. The film would be projected onto a piece of frosted glass one frame at a time; the animator would then place a piece of paper (or transparency) over the glass and trace it. Computers have not only sped up the process, they have also made it relatively easy to add special effects to any piece of film or video.

In this exercise, you're going to use Photoshop to create a 'lightsaber' effect for a short piece of video.

Procedure

  1. Get a piece of video. I will provide you with one for this exercise. When adding a lightsaber effect, it's easiest if you have footage of someone actually weilding some kind of saber-like object (a toy saber, a stick, a Wiffle bat, etc.). This will make it simpler to determine the proper length, width, and angle for the lightsaber blade.
  2. Convert the video to a film strip. In order to do this step you will need a video-editing application like Adobe Premiere or Adobe After Effects. Both can convert video clips to filmstrip files (.flm). Since most of you probably don't yet have either of these aps I will provide you with the converted filmstrip file. Hint: if you have one of these aps, and you want to create a film strip on your own, do only a couple seconds at a time; otherwise you'll end up with a huge, unweildy filmstrip file.

    3.  

    Rotoscoping the saber blades.

  3. Open the filmstrip file in Photoshop. Resave it as "sabers_with_auras" as a Photoshop file (not filmstrip).
  4. Create a new layer. Make sure this layer is selected.
  5. Zoom in on the top most frame (to about 200%). Choose the vector line tool . Choose the Fill Pixels option and make the forground color white. Set the line weight to 2 pixels.
  6. Trace over the lightsaber blade with the line tool. Don't worry that it's not quite as wide as the fake blade. And don't try to round-out the tip yet (we'll do that later). Draw just one line the length of the blade (it should automatically fill in white).
  7. Scroll down to the next frame and trace a line over the next saber blade. Repeat until you reach the end of the filmstrip. Option: on some of the frames the blade blurs into a wider 'wedge' shape. Instead of drawing with the line tool, use the Polygonal Lasso tool to trace around the blur area (don't use any curved lines). Fill it with white.
  8. Once all of the white sabers are drawn, select the lower layer (with the video stills). Open the Levels palette and change the upper output tevel to zero (this will turn the layer black).
  9. Flatten the image (merge layers). Save it again.

    10.  

    Adding the colored auras.

  10. Select Filters > Blur > Gaussian Blur. Set the blur amount to 2 pixels (the width of the blade).
  11. Select Levels. Change the lower input level to 30 and the upper input level to 50. This will round-out the sabers. The edges are sharp, but we'll fix that later.
  12. Duplicate the background layer. Call this new layer 'Outer Auras.' make sure this layer is selected.
  13. Select Filters > Blur > Gaussian Blur again. This time choose 4 (twice the line width).
  14. Select Levels again. Change the upper input level to 10.
  15. Repeat step 13 (Gaussian Blur set to 4px).
  16. Open the Curves palette (Image > Adjustments > Curves). If you want a red lightsaber, go to the blue channel and drag the right end of the scale (the output) down to the bottom. Do this also for the green channel; the beam will now appear red. For a green saber, lower the output on the red and blue channels. For a blue saber... (well, you can figure it out).
  17. Open the Levels palette again. Change the upper output level to 127 (this will darken the glow some).
  18. Double-click on the background layer. Rename it 'Blades' and drag it to the top of the layer list.
  19. Duplicate the 'Blades' layer. Call this new layer 'Inner Auras.'
  20. Add a Gausian Blur of 1 pixel (half the saber blade width) to the 'Inner Aura' layer.
  21. Open the Levels palette and set the upper input to 10.
  22. Do one more Gaussian blur, this time to 2 pixels.
  23. Open the Curves pallete and color these auras the same as you did the first.
  24. Drag the 'Blades' layer to the top of the layer list.
  25. Give it a Gausian blur of .75 pixels.
  26. Change the blending mode for the top two layers to Screen. The saber glows should now look complete.
  27. Flatten the image and save.

    28.  

    Compositing the final sequence.

  28. Select all, then choose Edit > Copy.
  29. Open the original filmstrip file again.
  30. Edit > Paste the labers into the filmstrip file.
  31. Change the blending mode on the saber layer to 'Screen' and violá, the lightsabers should be in place.
  32. Flatten the image.
  33. Save as a filmstrip file (yourName_lightSaber.flm).
  34. Give me a copy of your file.

    35.  

    Making the movie.

  35. Unless you have Premiere or After Effects that's as far as you can go. However, if you have one of those applications you can import this file and convert it back into a Quicktime (or other format) video.

 

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