# how to achieve this effect (opacity) - Macromedia Flash

Guys (and Gals too, I suppose), I'm trying to figure out how the background effect on this [url]http://www.mix-fx.com/balancedshakecasual.htm[/url] page is acheived. I assume it's just playing with the Alpha of some (somewhat) randomly-moving blue rectangles, but what I'm really stumped by is how the opacity is affected when the rectangles overlap. If alpha for two rectangles is 50% and they overlap, the overlapped alpha is still 50% - but in this effect, it appears to change. I'm assuming there's an easier way than manually computing the overlapped area and drawing that area with a higher alpha. Please make me smarter....

1. ## how to achieve this effect (opacity)

Guys (and Gals too, I suppose), I'm trying to figure out how the background
effect on this

[url]http://www.mix-fx.com/balancedshakecasual.htm[/url]

page is acheived. I assume it's just playing with the Alpha of some
(somewhat) randomly-moving blue rectangles, but what I'm really stumped by
is how the opacity is affected when the rectangles overlap. If alpha for
two rectangles is 50% and they overlap, the overlapped alpha is still 50% -
but in this effect, it appears to change. I'm assuming there's an easier
way than manually computing the overlapped area and drawing that area with
a higher alpha.

Anonymoose Guest

2. ## Re: how to achieve this effect (opacity)

If you look closer, there are at least three different alpha settings for
any given square. They are dynamically created, given a random alpha, and a
random position. Very simple to do. Two 50% alpha rectangles overlapping
each other appear more opaque. You can test this for yourself by creating
two rect movies with the same alpha place them side by side, and then one
over the other.

"Anonymoose" <Ihatespam> wrote in message
news:Xns948090B2276AIhatespam216.196.97.136...
> Guys (and Gals too, I suppose), I'm trying to figure out how the
background
> effect on this
>
> [url]http://www.mix-fx.com/balancedshakecasual.htm[/url]
>
> page is acheived. I assume it's just playing with the Alpha of some
> (somewhat) randomly-moving blue rectangles, but what I'm really stumped by
> is how the opacity is affected when the rectangles overlap. If alpha for
> two rectangles is 50% and they overlap, the overlapped alpha is still
50% -
> but in this effect, it appears to change. I'm assuming there's an easier
> way than manually computing the overlapped area and drawing that area with
> a higher alpha.
>

John D Guest

3. ## Re: how to achieve this effect (opacity)

> If you look closer, there are at least three different alpha settings
> for any given square. They are dynamically created, given a random
> alpha, and a random position. Very simple to do. Two 50% alpha
> rectangles overlapping each other appear more opaque. You can test
> this for yourself by creating two rect movies with the same alpha
> place them side by side, and then one over the other.
Yeah I'd found the problem - if you create two simple rectangles on the
same layer, of less than 100% opacity, and overlap them, the opacity isn't
ulative in the overlapped parts. But, if you do the same thing to a MC,
then it is. I was testing it with the first example and was puzzled why it
wasn't working, until I tried it with MCs instead.

Thanks.
Anonymoose Guest

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