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Cut Outs & Alpha Channels

Melodee Singer
Registered User
Join date: 20 Oct 2005
Posts: 9
04-25-2006 23:33
I'm sorry if this question has been answered already but I've recently noticed some grey hairs in the mirror since my quest for the answer in these forums and many sleepless nights, playing around in photoshop! :(

If you have an item of clothing or jewelry that has alot of cut outs, exactly what steps do you need to take to make the inside cut outs transparent as well?

I have a feeling that the answer isn't that complicated but after several attempts to figure it out myself, my brain went into hibernation mode on this one and is not cooperating with with the rest of me!
I would be very grateful to anyone who is willing to walk me through the process in simple terms!

Thanks to everyone who takes the time to answer these questions for those of us so eager to learn and for being so generous with your knowledge. SL would not be what it is today without you!

Melodee
Chosen Few
Alpha Channel Slave
Join date: 16 Jan 2004
Posts: 7,496
04-26-2006 10:02
Hi Melodee. First, I'd suggest reading the transparency guide stickied at the top of this forum, if you haven't already. Once you understand the basics of what the alpha channel actually does and how, your question will pretty much answer itself. Knowing that black on the alpha means transparent and white means opaque, the solution is to make sure the alpha channel is white where your fabric is and black where your cut-outs are.

For a simple example, let's say you want to make a pair of jeans with a rip on one knee. If you downloaded the complete template package, the lower body template comes with a jeans sample. Let's start with that. (If you downloaded the template seperately from the package, it might not have come with the jeans. In that case, you can download the jeans here).

Take a look at the alpha for the jeans. Notice it's white in the exact shape of the jeans, and black all around. Once you understand that all that white is what makes the jeans part visible, and that all that black is what makes the rest invisible, the obvious next step if you want to want one knee to be invisible is to paint black over that knee area on the alpha. Instant cut-out. Now let's say you want to put a big slash across the other leg. Simply paint a big black line across the corresponding area on the alpha, and there's your slash. Finally, let's say you want to make the whole thing look like it's been in a moth-infested closet for a couple years, and you want to turn it into swiss cheese. Well, cover the white area with tons of little black polka dots. Every one of those black dots will be a hole.

Of course, if you want those holes to look like an actual tears and frays in the fabric instead of just nice clean holes, you've got some more work to do, but the black/white principle is what's relevant to your specific question here. Anything black on the alpha will be totally invisible, anything white will be totally visible, and anything gray will be inbetween.

Oh, and just to thorough, if you are using the jeans sample that comes with the template, note that the sample alphas on the template are stored on layers, not yet as actual channels. To use that "Blue Jeans Alpha" layer, or any of the others, as an actual alpha channel, you'll need to copy it to a new channel first. Layers and channels are two different things. Storing all those sample channels as layers was just an easy way for LL to include them without messing anything up, output wise, since TGA images can only contain one alpha channel.
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Kala Bijoux
Material Squirrel
Join date: 16 Nov 2004
Posts: 112
04-26-2006 10:03
It depends on what exactly you are making.

But here's a tip that really helped me. (And I'm still using PS 6, so these instructions may be out dated for later versions - but I think they should still work).

After you've cleaned up your image (or drawn it), to select it, hold down control, and then go to the layers menu and click on the layer with the image. This will select your image and now you can save it as an alpha channel. This works FAR better than the magic wand.

I don't remember who told me this originally, but it was someone on this forum and it has saved me SO much time and frustration.
Robin Sojourner
Registered User
Join date: 16 Sep 2004
Posts: 1,080
04-26-2006 13:52
Command/ctrl clicking still works; but in CS2, you need to click on the actual thumbnail image, since Command/ctrl clicking on the layer itself now allows you to choose it as one of a series of non-contiguous layer selections. (Just like selecting non-contiguous things from other lists, within both platforms.)

And yes, this works much better than the Magic Wand. :D
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Melodee Singer
Registered User
Join date: 20 Oct 2005
Posts: 9
Thanx
04-30-2006 16:53
Thanks to all. Info from all three replies were very helpful and I'm on my way to HOLEY TEXTURES!

Melodee