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```Subject: Re: Visual explanation about Bongotweening?
Date: Tue, 14 Sep 2004 11:23:34 +0300
From: "Andrew le Bihan" <<andy@mcneel.com>>
Newsgroups: bongo```

Michael

Attached is a PDF which shows what effect the tweening options have on a

simple 1D scaling operation. This is the easiest place to start because

motion tweening is a little bit more complicated.

Your example, as it was tweening only along one axis was similar to red line

on the first graph. Acceleration has no effect on this object because the

speed never changes. Attached to this post is a version of your example

which shows all three lines on the graph with the same colouring. Above

this, in the same model, is an example which represents the 3 keyframes

curves. Note that the middle keyframe (on both the graphs and the model) is

not eased.

In Bongo, “Acceleration” is really the “Acceleration Smoothing”. In other

words, a high value will cause the change of speed to occur slowly. When

the value is low, speeds will change fast - at zero, they there will be an

instant change of speed from one value to the next.

Finally, motion. For positional keyframing, there is another tweening

property called “Curve Smoothing”. The effects of this can be seen on the

right of the model. This effects the smoothness of the path that the object

takes through space (note, that this doesn't have an effect on the X-only

stuff on the left of the model, because the path is always a straight line).

3 values of curve smoothness are shown. The effects of easing are also

shown on the far right curves.

It's becoming clear that some kind of visual representation of these values

is something we're sorely missing in Bongo. I'm going to give some thought

to this, and hopefully we can come up with a solution to this during the 1.x

release cycle.

Cheers

– Andy le Bihan

Robert McNeel and Associates