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How ratioing works

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To make more complex use of ratios, you'll need to know more about how it works internally:

The ratio, and the offset

Director takes the values you enter in the Ratio Panel, and converts them to a ratio and offset. Values in the source column are multiplied by the ratio, and have the offset added, to give the values in the ratioed column:

• The ratio is the value entered in the Ratio Panel.

• The offset is the difference between (the value of the source column at the lock frame, multiplied by the ratio), and (the lock value in the Ratio Panel).

The offset is automatically recalculated if the values in the source column change.

Inbetweening ratioed keyframes

Internally, Director uses the ratio and offset for inbetweening from a ratioed keyframe to the following keyframe:

• If a ratioed keyframe is followed by another ratioed keyframe that uses the same lock frame and source column, Director inbetweens both their ratio and their offset.

• Otherwise, Director inbetweens the offset only, to arrive at the value of the following keyframe (whether or not it's ratioed). The ratio remains constant.

Any inbetweening uses the timing stored in the ratioed keyframe. You can change this in the Properties window in the usual way.

Holding ratioed keyframes

If you set a ratioed keyframe to Hold, then its lock value and ratio remain constant until the next keyframe - and consequently so does the offset.

Creating new inbetweened keyframes

If you add a keyframe to a column, and the previous keyframe in the column is ratioed, then the new keyframe will also be ratioed. Its values are set so as not to change the scene:

• Its source column and lock frame are the same as those of the previous keyframe.

• Its ratio is the same as the old inbetweened ratio for the frame.

• Its lock value is set so as to leave the frame's value in the XSheet unchanged.

If necessary, you can then use the Ratio Panel to change the source column, lock frame, ratio and/or lock value.

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Animo NT User's Guide - Version 2.0 - 29 Jan 1999 Copyright © Cambridge Animation Systems