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11-10-2000, 05:01 PM
Ok, I have a problem it seems.

When ever I rotate an object, at large increments, it seems to cause the object to decrease in size. Is this supposed to happen? If it is, how do I avoid it?


Bob Hartzell
11-10-2000, 07:59 PM
When ever I rotate an object, at large increments
-> Are you referring to a morphing behavior or using the rotate transform? It is the behavior of morphing based on linear interpolation to make rotation of objects appear smaller during the rotation. My partner has pointed that out to me several times. Ask him Thursday when I leave and he hopefully answers questions on the forum.

11-11-2000, 12:41 AM
Morph Ink does the same thing. I found that if you use less tweens or convert the tweens to Keys you can compensate.

Richard W
11-15-2000, 11:22 PM
Johnie's fix is the one of the best right now, because currently, KoolMoves generates all tweens between key frames using staight line paths (linear interpolation). Linear interpolation has the advantage of being fast (easy for the computer to calculate). However, it causes a noticable shrinkage if something is being rotated through a large angle (over 20 degrees). For example, imagine a moving windshield wiper. Let's say in the first key frame it looks like this "\", then rotates to "/" in the next key frame. We would expect its upper edge to sweep out an arc. But, in linear interpolation, it just moves along a straight line. So, mid way through the rotation, the upper edge is exactly the same hieght as it was in the first key frame. One fix is to turn that middle tween into a key frame and scale it so it's top edge lies on the swept out arc. But, if you don't want to guess how much to scale by, here is a way to have that work done for you. Make a copy of the first key frame and paste it inbetween your two key frames. Then, in that new key frame, rotate the wiper half way (make sure that you first move the center of rotation to the lower edge of the wiper). In the future, KoolMoves will suport tweens generated by a transform matrix. Then, a rotate will be a rotate rather than a linear approximation of one.

11-16-2000, 04:51 PM
Thanks, yeah I have found that to be a problem. How far do you and Bob plan to go with KoolMoves(bones) just curious, what features do you hope to have implemented?


Richard W
11-16-2000, 10:31 PM
Brad- Bones and related schemes have been implemented in various ways in various systems. Some are difficult to use an others require too much hand correction. We hope to provide an approach that is both easy to use and a great boost to animator productivity. Obviously, it would be nice for our bones to avoid the rotation shrinkage problem.

11-16-2000, 11:41 PM
I'm glad we have a forum where we can safely and discreetly discuss the rotation shrinkage problem.

11-17-2000, 08:51 AM
Hey when you get it fixed, it might be an interesting option for rotation(a rotation with pulse effect):)