smooth ,linear etc.

[neil]

I know this may be a stupid question but what is the difference between linear,smooth etc. on the zoom, pan rotate?

I have tried altering them but can notice no change.

Please excuse my ignorance.

Neil

[Lin Evans]

Hi Neil,

First, no question is "stupid" - some answers may be, but never feel bad about asking a question.

Linear zoom simply means that if you were to divide time between the start and end of a zoom into equal divisions, exactly the same amount or percentage of zoom would happen between each increment. So, for example, if you had a zoom set to enlarge an image to double its original size and you wanted this to happen over 20 seconds, at 10 seconds the image would be 1.5 times or one and one half its original size.

Non-linear zoom means that things happen in different proportions at different times. For example, in a smooth non-linear zoom the zoom first begins very slowly, then speeds up and maintains a constant proportion of change then just before it ends it slows down again.

As you know, when a DVD is being rendered, usually for each second of time 30 new images are generated, each new image showing a slightly different movement of the subject. For a linear zoom each image in a one second period would represent 1/30 th of difference from the previous image to the image at one second having passed. For a "smooth" non-linear the first images might be only 1/50th difference, etc., then gradually they would acceleate to 1/30th and nearing the end of the period of change they might again be only 1/50th different. So the effect is that at the beginning and end of the movement, the motion would slow down and rather than an abrupt or "jerky" start and ending the start and ending would look very smooth.

I used smooth non-linear as an example, but other non-linear movements could be to start movement slowly then speed up throughout or to start fast then slow down near the end. So non-linear simply means that things happen at different speeds at different times while linear means they happen at the same speed over time.

For now, I would suggest that you test this by using on the begining and one keypoint. Set your time for a slide to 10 seconds using the Main tab from "custom" function from Objects and Animations screen, Put a keypoint at about 9 seconds then drag the bounding rectangle to make an image get larger by about 50 percent. Set the zoom to linear and watch. Now set the zoom to smooth and watch.

Finally, watch the tutorial on how to change from linear to non-linear because when you have more than two keypoints, you must not only click on one of the non-linear functions but also "separate" keypoints via the "setup" for each slide.

Here is a link to an AVI file I created explaining this:

http://www.lin-evans.net/tutorial/nonlinearavi.zip

Best regards,

Lin

I know this may be a stupid question but what is the difference between linear,smooth etc. on the zoom, pan rotate?

I have tried altering them but can notice no change.

Please excuse my ignorance.

Neil

[neil]

Lin,

Thanks very much for explaining this so well,and also the excellent tutorial.

I now understand what its all about.So I can now have a play about with it.

All the Best Neil