Alpha Channels – Please Help

[Elvis Deane]

Is it possible your alpha channel wasn’t saved out of Photoshop properly? I know that with TIFs in Photoshop, there are two places you have to check a box to export the alpha, the Save options in the Save As dialogue box, and in the Tiff Options box. I don’t have Photoshop here, so I can’t say for sure if the same is true for PNGs or TGAs.

The other thing you can try in pI is to load the image with the alpha as your Background image, and turn Get Transparency from Layer on in your emitter’s color options. It won’t give you exactly the same effect as Area Emitter Masks, but it should at least let you know if your alpha channel is loading up.

With Area Emitter Masks, you should always make sure that the emitter is in the exact center of the stage. Since the image is loaded into the emitter, it gets tied to the position of the emitter. This might not explain your problem, but it’s possible that if the center of your emitter is too close to the edge of the screen, your particles are appearing off screen somewhere.

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Elvis Deane!
The particleIllusion FAQ
particleIllusion Resources and tutorial CD
Astounding Adventures

[Alan Lorence]

Whenever I have a question about what the alpha channel looks like in pIllusion, I’ll load the image on a layer, then turn on transparency for that layer. Then I’ll select a crazy background color and see if the alpha channel is what I expected.

Alan.
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