Making textures with GIMPshop

From ZoomLabWiki

1 What?
2 What with?
3 How?
4 And lastly
5 Further reading

What?

In this tutorial, I'll show you how to turn an image into a texture for use in Second Life, the online virtual world that's all the rage among the kids these days. Follow along at home as we unravel the mysteries surrounding the picky, picky file specifications required by the Model T Metaverse.

What with?

GIMPshop is a version of GIMP, the powerful, free and open source image editing application, that's been modified to make it act more like Adobe Photoshop, the powerful, expensive, closed source image editor. I like GIMPshop because I'm used to using Photoshop. We're going to use GIMPshop to make a texture with transparency for use in Second Life.

This tutorial was written for users of GIMPshop 2.2.8 on Windows XP. Mac OS X users should have little difficulty using this -- substitute "Cmd" for "Ctrl" and you're halfway there.

How?

download GIMPshop. Go to the GIMPshop site and download the latest version for Mac OS X or Windows. For the Windows version, look for the link called "Windows users can download an installer for GIMPshop 2.2.8". Download that file and run the installer. It'll put a shortcut on the desktop: double-click that shortcut to open GIMPshop.

Go to the Kids Connect Flickr photos to get an image to work on. I would recommend finding one that has an object/person/thing in it with nothing much behind it except sky. For example, the following image taken by Amanda has two birds on a wire. It'll be easy to cut those birds out of the background because you can auto-select the sky in a couple clicks. If there were trees or other chaotic-looking thingies behind the birds you'd have to do a lot more manual tracing.

We want to use the original, high resolution image, the reason being that you'll never know if you might want to make a big, high res version at some point. Click the "All Sizes" button above the photo.

On the next page, click the "Download the Original size" link. If you're prompted for a location to save it to, save it to your desktop. Go to your desktop and rename the file from the "204861023_4fbcaf8611" gobbledy-gook to something descriptive like "birds-on-a-wire.jpg". Good job, have a cookie.

In GIMPshop, go to the menu File > Open..., navigate to the desktop and open the photo. Now we get to the fun stuff.

the File menu

the Open File window

So to go to the Desktop in the Open File window, you'll double-click on "Desktop" in the left-hand pane and the Desktop files will pop up in the center pane. Select your image file from the center pane and either double-click it or click the Open button.

Choosing the Magic Wand

Now for the fun stuff: we're going to remove everything except the birds and the wires. Select the Magic Wand tool from the tools window. Click in the sky next to the birds. It should look like this image, with little black and white lines moving around the selected area. This genius user interface innovation is known as 'crawling ants.' A pigeon covered with ants! Ewww! Mommy, make them stop!

Note: In the Tools Options window (below the Tools) I used a threshold of 20.0, which left a little blue halo around the birds and wires. If I wanted to get it really clean, I'd play around with the threshold settings and maybe use 'feather edges', but this is a quick and dirty job. If you're getting too much of what you want to keep, dial down the threshold (try 5.0); if too little, try higher, say 30.0. Sometimes all you need to do is...

Hold the Shift key down and click in the other areas you want to remove (the rest of the sky).

Note: if at any time you mess up and want to undo something, hit Ctrl + Z a few times to step backwards through your last few actions. If you run out of Undos and it's still messed up, do File > Revert.

You've selected all the sky: congratulations. Now do Edit > Clear (Ctrl + K) to delete all that. The sky should be replaced by a bunch of white and grey squares.

Note: If it gets filled with white or black instead, that's because your image doesn't have an Alpha (transparency) channel. Go to Layers > Transparency > Add Alpha Channel. Try clearing (Ctrl + K) the areas you have selected again -- it should work. If it doesn't, go check the Gimp help files, don't ask me. ;)

Now you should have two birds on two wires and a brick wall, all on a background of white and grey squares. Don't you think brick's just a bit too tawdry and bourgeois? Mmmm...me, too. Let's delete it. But before you do that, grab the bottom corner of your image window (the blue border on Windows) and drag it out so you've got some empty (beige) space around your photo.

To get rid of the brick wall, use the Rectangular Marquee tool. No, I don't know why it's called a 'marquee,' even though it's so much more like a square lasso. Click and drag a rectangle around the brick wall. Good. Hit Ctrl + K (Edit > Clear) to delete the wall. Super duper!

You're almost there. Second Life likes its images files to have dimensions that are powers of two, e.g., 256 x 256, 512 x 512, or 1024 x 1024 pixels. Let's make ours 1024 x 1024 -- we can always make a smaller one later.

Note: for more on image sizing for SL, see this excellent thread on the SL Fora.

Go to Image > Image Size... Make the largest dimension (in my case, the width) 1024 pixels. Hey, it's already 1024! I'm set. Don't try and change the other dimension to 1024 -- it'll stretch the image. Hit the Scale button.

To make the height 1024, we'll add transparent areas along the top and bottom. Go to Image > Canvas Size.... (right below Image Size -- come now, keep up)

Click on the chain symbol, which allows you to change the width or height without the other dimension being changed by the same ratio. Change the Height to 1024 pixels. Hit the Center button so that your birdies get stuck in the center of image. This will make it easier to work with in Second Life...I think. (Experienced SL artists, if I'm wrong on this, please correct this page. :) Now hit Resize.

Whoopee, last part! Go to File > Save As.... Give the file a descriptive name, choose a save location (click "Browse for other folders" if necessary", then click "Select File Type". At this point it would be prudent to save a working copy, so scroll down through the list of types and choose "Gimp XCF image" at the top of the list. Hit Save. Then do File > Save As... again and select "TarGA image" this time. (If you have any layers in your file, it will prompt you to Export a merged version. Do so.) Then in the "Save as TGA" window, uncheck "RLE Compression" and "Origin at bottom left" -- we don't want those. No, I don't know why. Click OK.

Login to Second Life and do File > Upload Image. Select your Targa file. In the little Preview window that pops up, your transparent areas ought to be transparent. If not, you've done something very bad and should be punished. Go to the top of the page and repeat the process. Wear a hair shirt. Hit yourself in the head with a claw hammer...using the claw end. If it's transparent, good job! Good boy/girl! Have a cookie.

And lastly

I wrote this tutorial for our students in Kids Connect because we decided to use GIMPshop and there were no GIMPshop Second Life texturing tutorials out there. I hope it's useful for you. If you think this tutorial sucks or lacks a certain...I don't know what, register for our wiki and make it better. If there's a better one out there, link to it. Thanks!

Making textures with GIMPshop

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