Cool (but odd) Flash behavior

[slrobinson]

I've been using Flash and have run into some odd behavior when trying to apply things to grouped objects. In the attached file, the balls should all act the same (I think) but they don't.

Grouping them should give them a common center for rotation and stuff, and that's what I tried to do. Unfortunately, they seem to have a mind of their own.

Anyone know why and how I can control the behavior?

[Intbel]

This works:

[slrobinson]

Thanks Intbel. That works until you try to shrink the group. When I take your example and apply a change in size of 50%, it exhibits the same behavior. To me, that means the odd behavior is somehow liked to changing the group's size.

[Intbel]

Thanks Intbel. That works until you try to shrink the group. When I take your example and apply a change in size of 50%, it exhibits the same behavior. To me, that means the odd behavior is somehow liked to changing the group's size.

I didn't have that problem.
Just reduced by 50% with no deformation:

[slrobinson]

Sorry, I guess I'm not being clear. The problem occurs when you rotate a group of things AND shrink them at the same time. You can use the original file I uploaded to see what's happening.

I agree, "Can't is not an option" so I've already found a work-around (use a bitmap of the group) but I'd still like to understand why the original file doesn't behave.

[Intbel]

Sorry, I guess I'm not being clear. The problem occurs when you rotate a group of things AND shrink them at the same time. You can use the original file I uploaded to see what's happening.

I agree, "Can't is not an option" so I've already found a work-around (use a bitmap of the group) but I'd still like to understand why the original file doesn't behave.

Both files I posted were your files.

Having sorted the rotation, to resize, group in each frame was selected and percentage value of fifty entered as opposed to re-sizing by dragging.

[WolfMoonHP]

This is truly strange behavior (behaviour for your Brits). I used the file that Raymond posted, added a frame, all went well. But when I changed the size of the grouped object in the new frame, some of the balls behaved independently.

I had something like this happen in another animation I did at Yule, when part of a grouped image did not move with the rest of it. Turned out that I had named the ornaments before I put highlights on them, and the highlights animated differently than the ornaments they belonged with, even though they had been grouped.

I took the ring of balls, made a bitmap copy, then created a new animation. Rotating and changing size work smoothly.
---
Will

[ren2980]

I also made a test but without problem. First, I made some circles, colored and arranged them within a larger round circle.
It runs OK.

[slrobinson]

The odd behavior doesn't show up until you try to both (rotate and shrink). I can't make it exhibit the odd behavior unless I do both at once. Also, it doesn't seem to happen if I just rotate and expand.

I've received a reply from Xara support and they're looking into it.

In the mean time, make a bitmap of the group and it should work okay. The only obvious failing is that bit maps don't scale as nicely and are larger.

[slrobinson]

I got an answer from Xara and I finally am posting the answer. The odd behavior is the result of (essentially) rounding error in digital positioning. If, for example, you have an object placed at an arbitrary position on a circle, then you shrink the circle, the position can change very slightly when Xara calculates where it goes on the smaller circle.

If that position is just microscopically clockwise from the original, when you tween clockwise between the two, it will move only that microsopic amount.

Understanding this, it's easily fixed by forcing the positions manually.

Thanks Xara ... perfectly understandable, and manageable.