...and what it does
That little dot which you move to get the creature's feet centered on the cross hairs of the Animation Editor's screen is actually the top left corner of the graphic being displayed. And like stamp placement on a map, the white margins on a graphic affect where the stamp will ultimately appear. Most graphics are trimmed so that no margins exist.
I'm working on an animation of a snake and ran into some uncommon problems. There are 8 frames in each of 8 directions for the "walking" sequence and a like number for the attack sequence. When I started adding the pictures to the animation, the snake was jumping all over the place, particularly when the snake changed directions. With almost any other creature this would not happen because the feet would always be at "ground zero" and the creature's height and breadth were mostly constant.
I began moving that little dot around to get the snake into the right spot for each frame and soon had a maze of dots I couldn't possibly sort out. Centering the head did not work either because the head is supposed to weave back and forth.
I've discovered a way to make all the pictures show up correctly in an animation without having to plot the placement dot for each individual graphic. Here's what I did: I determined that the "ground contact" point on the snake was about 1/3 down the length of the snake. I then opened each graphic in GraphicConverter and charted the X and Y distances (in pixels) from the top left corner of the graphic to the "ground contact" point. Next, I went back to GraphicConverter and added clear margins to make the X and Y distances the same for every picture. (For example: 90, 42) Now I went back to the animation editor and set the first placement dot at 90, 42 and everything lines up perfectly when the animation is played.
