hide random home http://www.newtek.com/3d/tutorial/mathmorf/setting.html (Amiga Plus Extra No. 5/97, 05/1997)

Setting Up the Basic Motion

  1. In Layout, if the fish is not already loaded, clear the scene and load it.

  2. To get a good view of the fish, view through Perspective and change the view rotation to:

  3. On the Scene panel, change the scene length to 60 frames and turn off camera visibility.

  4. Keyframe the fish at Z = 6 at frame 0 and Z = -4 at frame 60. The fish now swims in a straight line towards negative Z.

  5. Apply the MathMorph Displacement Map plug-in. In the plug-in Options panel, set the Point X channel to sin(z):

    This distorts the shape according to a sine wave. Make a preview and notice that the fish is bent, but doesn't change shape over time.

  6. To make the fish change shape over time, change the X channel equation to sin(z + t). The "t" is for time (in seconds). This means that 1/30th (.0333) is added to the z part every frame.

    Make a preview and notice that, although the shape changes with time, it's too slow.

  7. To make the shape change faster over time, change the equation to sin(z + 7*t). Multiplying time by 7 makes the shape change seven times faster. You can use a different multiplier to get a different effect, but 7 works well for this tutorial. (Besides, everyone knows seven is a lucky number.)

    Make a preview and notice that something looks "wrong" with the motion. It's much faster, but it is backwards; this motion wouldn't push a fish through the water. In fact, what this looks like is a fish trying to swim upstream but getting pushed backwards as it does (if you imagine the fish facing the other way).

  8. To make the fish swim in the "right" direction, change the equation to sin(z - 7*t). Changing the plus to a minus just makes time go the other way for the fish.

    Make a preview and notice that the fish swims the right way now.

This simple formula sets up the basic motion of a fish swimming using MathMorph; however, there are a few changes that can fine tune the fish swimming motion.
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