Advice on O&A

[mbskels]

I have used PTE for several years but only got round to looking at O&A recently.

I am trying to produce a realistic effect to show an object "growing" from a point vertically on the Y-axis - for example a tree growing from zero to full size as in time lapse photography. I have tried various combinations of pan/zoom/opacity but cannot achieve a realistic result.

I have added the object as a png to the main slide and positioned it at its final position at 100% zoom and at 5s on the timeline. I then took the x,y co-ordinates at the point at the centre of the base of the object, copied the keypoint and moved it along the time line to its start position at 2s. I set the zoom x,y to zero on this keypoint.

The end effect using this technique is not what I am looking for. At best the object appears to lift up through the z axis until it is full size rather than "growing" vertically on the y-axis. I have also tried disconnecting the x,y zoom parameters but with no success.

I would appreciate if someone could advise if there is a better technique to achieve this effect.

TIA

Malcolm

[xahu34]

Malcolm,

If you set the y-coordinate of the center to 100 (for both key frames), does this provide the effect that you would like to have?

Best regards,

Xaver

[fh1805]

Malcolm,

You need to set your tree image up so that it's "centre point" is anchored at its bottom edge.

Starting afresh with your "tree" object newly added to a background image, proceed as follows:

Reduce the size of the "tree" object to 50% with the x,y zoom values properly connected (this is purely so you can see the effect of the other changes we're going to make).

Now change the right hand field value for "Center" to be 100. If you do this by using the little arrowhead beside the field you will see the centre marker of the object image begin to move towards the bottom edge of the object image. Once you understand what is happening you can key in the value 100.

Next, go up to the Pan fields and set the right hand field value to 100 (This will move the entire object down to align on the bottom edge of your background image)

Reduce the zoom to, say, 5%. Add the second keyframe and set the zoom to, say, 75% leaving all the other settings untouched and play it.

Is that what you wanted?

regards,

Peter

[xahu34]

Peter,

when reading your post and comparing it with mine, I ask myself which procedure is more helpful: just referring to the crucial point or giving a detailed description. I'm not sure about the answer.

Best regards,

Xaver

[fh1805]

Xaver,

I hope I didn't offend you by giving the fuller explanation of the solution that you indicated in your post. The fact that I gave a step-by-step explanation is probably a legacy from my last job before I retired: I was a driving instructor!. I found that the pupils learned best if they understood why they were doing what I was asking them to do, rather than simply getting them to do as I said, with no understanding as to why.

If an apology is required from me, consider it given. No offence was ever intended.

regards,

Peter

[mbskels]

Hi Xaver and Peter,

Thanks both very much for your help. It is certainly a great improvement over my attempts.

Apologies for not replying earlier but I was called out after posting and just got back to the office.

Thanks again

Regards

Malcolm

[xahu34]

... I hope I didn't offend you by giving the fuller explanation ...

Peter,

I would never expect that you intended to offend any other user in this forum, not even me I have made my experience with teaching students mathematics, and I think that it's often better not to present complete recipes, but just giving hints to explore the situation and to learn general principles. Maybe, what I did above wasn't a good example.

Best regards,

Xaver

[fh1805]

Xaver,

We have two different teaching backgrounds; two different teaching styles - both of them correct for the situation and pupils that we each had. If I had left my pupils to work out a particular traffic problem just by giving them hints, we would have had some serious accidents! Even when I told them exactly what to do we still had some scary moments.

regards,

Peter