Help request: Using Rotate animation

[fh1805]

I've been using PTEv5 since July and feel comfortable using Pan, Zoom and opacity features of O&A.

I've just embarked on my first serious attempt to come to grips with Rotate and am getting a little confused - and on one point I'm totally baffled.

First the confusion:

I had assumed that, for any object that I wished to rotate, the value that I entered into the Rotate field was the number of degrees of rotation that would occur during the interval between the previous keypoint and this one (positive numbers being clockwise and negative numbers being anticlockwise).

What seems to be happening is that the value is actually being processed as "the number of degrees of rotation from origin zero to be achieved since previous keypoint".

An example might make things clearer. I'm constructing an animated Introduction sequence and I have a piece of text that I want to move from the centre of the screen up to the top left corner, then down to the bottom right corner and then back to the centre. The simple pan movements are working fine. But I want the text to rotate as it travels. The first keypoint defines it's normal, at rest, dead centre position. The second keypoint defines its position in top-left corner. This keypoint has rotate set to -1440 (four complete revolutions anti-clockwise). The third keypoint defines its position in bottom right corner. This keypoint has rotate set to 2880 (eight complete revolutions clockwise). What actually happens is that the text object, whilst travelling from top-left to bottom-right, actually rotates clockwise a total of 12 times - it undoes the -1440 and then applies the +2880. Is this how it was designed to work? (And, yes, I have read Lin and Jeff's tutorial but I didn't spot anything that explained this sort of effect).

The point of bafflement is as follows:

In the same sequence (actually on the same slide) I have a piece of text (the words "Presented by") that I would like to have move around the screen like a second hand sweeping around a clockface - anchoring them at the centre of the right hand edge of the text. I have gathered from Lin and Jeff's tutorial that this should be possible using a combination of Rotate values and Center values but I can't seem to find the right combination. Is what I want possible? If so could some one please enlighten me?

[Lin Evans]

Hi Peter,

Link to Sample:

Yes, you can do this. I've provided a sample:

Essentially, you need to remember that when you rotate something in one direction, you need to "unwind" if you want to rotate the same object in the opposite direction. So if you rotated counterclockwise to the left top and wanted to rotate clockwise to the bottom right you would go from a negative through zero to a positive.

Let's say you rotated -1440 for four revolutions of your text to the top left and now you want to rotate to the bottom right four times. So you set your first keypoint (when the text was in the center) to zero rotation. The second keypoint to -1440 and the third keypoint to zero. This "unwinds" from -1440 in a clockwise direction to zero again. If you wanted fewer rotations in the clockwise direction then you would use less than zero or a less negative number but still a negative number. If you wanted greater than four rotations you would use a positive number. So if you wanted five clockwise rotations you would use 360. Play with it a bit and it will become clear.

For the text sweeping like a second hand you must move the center from the default point (center of the bounding rectangle as if you were to draw diaginal lines from opposite corners - where they intersect) to the edge where you want the rotation. For example, if you want the text block to go clockwise and rotate on the left edge, click on the green "dot" at the center of the bounding rectangle, hold down the keyboard shift key and drag the dot to the center of the left vertical bounding rectangle border. Do this at the start "AND" at the ending keypoint and set the second keypoint to 360 to sweep the text in a clockwise direction once, etc.

Let me know if you need more help:

Lin

[fh1805]

Hi Lin,

Many thanks! Your explanation has cleared all the confusion and bafflement from my mind. I've programmed the effect I wanted. The text item "Presented by" now slides from its original position to where I want it to sweep the clock face, does one complete sweep and then slides back to its original position.

I also now understand that, if you want to do some rotation and then after that do some panning you have to supply the end-position rotate value on all subsequent keypoints otherwise, as you pointed out, it unwinds itself. Actually this has worked in my favour on the two items that traverse to and fro on the diagonals. Because of my misunderstanding when I programmed them they both do a very rapid "unwind" at the end of their traversing. This works absolutely brilliantly with the music I'm using. A classic case of what I call a "serendipity moment".

[Lin Evans]

Hi Peter,

That's great that it worked out the way you wanted.

Best regards,

Lin

Hi Lin,

Many thanks! Your explanation has cleared all the confusion and bafflement from my mind. I've programmed the effect I wanted. The text item "Presented by" now slides from its original position to where I want it to sweep the clock face, does one complete sweep and then slides back to its original position.

I also now understand that, if you want to do some rotation and then after that do some panning you have to supply the end-position rotate value on all subsequent keypoints otherwise, as you pointed out, it unwinds itself. Actually this has worked in my favour on the two items that traverse to and fro on the diagonals. Because of my misunderstanding when I programmed them they both do a very rapid "unwind" at the end of their traversing. This works absolutely brilliantly with the music I'm using. A classic case of what I call a "serendipity moment".