Cut out textures

How is it possible to have blank areas (like a tree) on a texture? I tried having a blank background on MS Paint or something but it shows up white when I upload. Any advice?

Photoshop.
Alpha Textures.
Targa,

Erm, what?

Google it.


But in a nutshell:

see-through areas in a picture are possible through an "alpha layer". Just as a picture has a red, blue, and green layer, the alpha layer tracks how opaque a given pixel should be.

However, the only image format that SL accepts that uses alpha layers is TGA, aka Targa.

This means you need to make an area transparent, save that to the alpha layer, and save as a TGA. And you cannot do this in Microsoft Paint, which is a pretty sad excuse for a graphics program (but it is in every Windows install, I suppose).

The three most-used programs seem to be Photoshop (pricey, but it'll do anything with pixels you ask), Paint Shop Pro (somewhat less pricey, not quite as extensive) and the GIMP (totally free open-source software, in theory just as capable as either of the other two programs, but it has a user interface designed by programmers, not The Rest Of Humanity).

Hi Steelth. Welcome to SL.

Let me offer you a more complete explanation of how transparency works for images in 3D graphics programs like SL. As has been mentioned, it is controlled by an element called alpha, but contrary to what was said in the previous post, there's no such thing as an "alpha layer". It's an alpha channel. Since you don't yet know much about graphics, that probably doesn't make too much sense to you right at the moment, but trust me, layers and channels are two terms you do not want to confuse if you want to learn this stuff properly. They're both very important, and very seperate components of digital imagery.

You'll find that this forum is the only place on the face of the earth in which people have the unfortunate tendancy to confuse the two words. It's something I've been actively trying to combat for close to 2 years now, but somehow it comes back every few weeks. For a detailed description of the what layers and channels are, see this thread.

As for how exactly channels control color and transparency, here's my standard explanation. Understand that this conceptual information of how digital images are constructed at their most basic level may or may not be absorbable by you until you actually begin using a program that allows you to take advantage of the knowledge (not MS Paint), but once you get started for reall, this will make perfect sense.

[U][B]Color Space & Channels[/B][/U]
Images designed to be shown on a color screen exist in what as known as RGB color space, meaning they are comprised of the three primary colors, red, green, & blue. The relative brightness of each of these primary colors in each pixel determines each pixel's actual color. For example, a pixel comprised of equal values of red and blue without any green would appear to be purple.

When taken seperately, the individual values for red, green, or blue for the whole picture are represented by a grayscale image called a channel. In an individual channel, white represents the maximum possible concentration of color and black represents the absense of color. Shades of gray represent amounts of color that are less than the maximum. The darker the gray, the lesser the concentration of color. The lighter the gray, the more color is present.

[U][B]Channels & Transparency (Alpha Channels)[/B][/U]
Images that have transparency have the same three primary color channels and also have a fourth channel, called Alpha, which represents opacity. In the alpha channel, white represents comlete opacity and black represents the absense of opacity (transparency). Shades of gray represent semi-transparency. The darker the gray, the more transparent. The lighter the gray, the more opaque.

So, for example, if you are making a bikini top for your avatar, the alpha channel would be white in the shape of the bikini top, and black everywhere else. The white part makes the bikini top 100% opaque so that you won't be able to see through it when it's on the av, and the black part makes the rest of the image invisible so that there appears to be nothing on the av's arms, stomach, etc.

Specific instructions for how to create an alpha channel will vary depending on what graphics program you choose. Once you pick one, I'll be happy to provide you with a step-by-step tutorial for your particular software.

So, which one should you choose? Well, if you've got the money, Photoshop is the clear winner, no question. It is the industry standard, and easily one of the best programs of any type in existence for any purpose, certainly THE best raster graphics editor there is. If you don't want to spend the money, then the GIMP is almost as good, and it's totally free. Coupled with the GIMPshop plugin, it performs almost exactly as Photoshop does. Pantshop Pro is another popular alternative, but personally I've never been a fan of it. It just doesn't make sense to spend money on the third best solution when the second best is free.

Whatever you do, stop using MS Paint. As Aliasi said, it is one of the worst excuses for a program that has ever been. It's included with Windows, so everyone has it, but no one should ever use it. It's a bad, bad program. Among its many deficiencies, it can't create transparency of any kind, let alone Targa files (TGA), the industry standard format for textures. Trying to use Paint to make textures is like trying to use Notepad to write a novel, or for a non-computer analogy, it's like trying to chop down a redwood forest with a paring knife. Sure, it can be done, sort of, but it takes a thousand times longer, and the end result won't be very pretty.

When you've obtained one of the 3 good programs mentioned above, come on back with any questions you might have. Several of us volunteer time here every day helping people learn this stuff. Good luck and have fun with it. Happy holidays!

I meant channel, truly I did. I usually know what I mean to say, but these durn clumsy hands get in the way.

I haven't been playing SL very long, but even then, I find this question repeated often. I'd like to suggest the post that contains the most fluid, and well written answer to be upgraded to a sticky.

How-to stickies would really help out.







This concludes Enoch's broadcast day. Merry Christmas, and all that Yule-tide jazz.

Here's some visual reference using a typical tree/shrub for anyone who has Photoshop and is textually challenged.

Step 1. Starting off with an image that you'd like to 'cookie cut' out. You need to create an alpha channel as shown. Click on the small triangle button and select 'New Channel'

Step 2. Go to the alpha channel once its created. The alpha channel is your cookie cutter channel. Anything that falls on the white bits will show up. The black ones will be transparent. In this case, the background of the tree. So, you actually have to draw in the whites here.
The RGB channels can be turned on along with the alpha channel to do this.
It shows up as an overlay. In my case here, I've used the default red colour as the overlay. Can be seen in the step 3 pic.
I normally use the magic wand to select the outlines if the image is clean enough. Then go to the alpha channel using the selection to paint in the whites.

Step 3. Save as your image as a .TGA file. Remember to check the alpha channels check box. Click save.

Step 4. An option box will come up. Select 32 bits/pixel. The default option is 24 bits/pixel. But this is for images with no transparency information.

Step 5. Upload image to SL. Make sure the transparent bits show up. If not, cancel the upload.

Just experiment a little, as it costs nothing, since you can abort the upload if something goes wrong.

Thank you! This explained alot to me..I could never figure out why I would get just a little bit of white over the breast area when trying to make clothing.. I had no idea i needed to go color it in black on the alpha channel. This really helped alot! Thank you!