In this tutorial, you will learn how to add an alpha channel to your sculpt map to protect it from theft by screenshot and how to add a watermark to the alpha channel to let people easily tell that you made it.

A Thief!  A Thief!

Many people don’t like to include modify permissions on their merchandise to protect themselves against theft, however, there is a way to protect your sculpties from theft and STILL include modify permissions.

The easiest way to steal an object’s sculpt map is the screenshot method. The thief opens up the edit window, clicks on the sculpt map, and then takes a screenshot. He’s then free to crop the sculpt map from the screenshot and re-upload it into Second Life.

However, there’s a cure.

The Theory

Any builders will probably be familiar with Alpha Channels in Second Life. If you’ve ever seen a wall texture with window cut out of the middle, this is done with an Alpha Channel. Second Life textures can use alpha channels to add transparency to an image – but the transparent parts can still retain their RGB values! So in theory, you can create a completely transparent sculpt map that still has the RBG data necessary to form your sculptie.

Only in theory?

Well … it really depends on your image editing software and the file format you choose to save in. In my experience, only Photoshop and GIMP can do EXACTLY this. Other applications can get close enough, though.

Application-Specific Guides

After trying to help my sister reproduce alpha channels in Paint Shop Pro and Gimp, I’ve come to the conclusion that every image editor does this so differently that I need to create a guide for each one.

Photoshop
Photoshop Elements
PaintShop Pro
The GIMP

Alpha in Photoshop

To add alpha protection to your sculpt map in Photoshop, you have to use either the TGA or PNG file formats. How you add the protection depends on which file format you decide to use.

TGA Format

The TGA format in Photoshop is the most direct and (in my opinion) easiest method for adding an alpha channel to a sculpt map.

All we have to do is go into the channels menu (shown left) and hit the “New Channel” button on the bottom of the menu. (It looks exactly like the New Layer button in the layers menu.)

By default, Photoshop will make a solid black alpha channel.  This will make your image completely transparent, which is fine.  I, however, chose to paste a black and white version of my logo into the channel so it will show up on the sculpt map when I upload it to SL.

Now save the file as TGA. Photoshop will bring up a dialog, asking you a few things. Just make sure that it’s set to 32bit. Nothing else matters. Save and upload into Second Life.

PNG Format

As much as I prefer TGA alpha channels, there are people who swear by PNG format because.. well, you can see the transparency directly on the image, rather than having to interpret the alpha channel.

But NOTE to png users. In order to make the file size smaller, Photoshop does NOT save RGB values for completely transparent pixels in a PNG image. So if you use PNG, all of your pixels have to be at least slightly visible.

In the Layers menu, make the background layer into a normal layer. This can be done by double-clicking the background and hitting “OK” on the dialog that comes up.

Now change the opacity of the layer to 1% or higher. This will still keep your sculpt map from being stolen while forcing Photoshop to save the RGB information to the sculpt map image.

In order to get my logo on this one, I created a duplicate of the sculpt map layer, turned the opacity up to 100%, then cut my logo out of that top layer.  Then hit CTRL-E to merge the two layers

Save as PNG with no interlace and upload to Second Life.

Alpha in Photoshop Elements

To add alpha protection to your sculpt map in Photoshop Elements, you have to use the PNG file format.

In the Layers menu, make the background layer into a normal layer. This can be done by double-clicking the background and hitting “OK” on the dialog that comes up.

In order to make the file size smaller, Photoshop does not save RGB values for completely transparent pixels in a PNG image. In order to retain the RGB data, all ot the pixels need to be at least slightly visible.

So change the opacity of the layer to about 1% – NOT 0%. This will still keep your sculpt map from being stolen while forcing Photoshop to save the RGB information to the sculpt map image.

In order to add my logo watermark, I created a duplicate of the sculpt map layer, turned the opacity up to 100%, then cut my logo out of that top layer.  Then hit CTRL-E to merge the two layers.

Save as PNG with no interlace and upload to Second Life.

Alpha in PaintShop Pro

To add alpha protection to your sculpt map in Paint Shop Pro, you can use either PNG or TGA. How you do this is dependant on which file format you choose.

PNG Format

Open your sculpt map, then find the Layers palette on the right. Near the top, there’s an opacity slider for your background layer. PhotoShop will not save the RBG data for completely transparent pixels, so slide the opacity down to 2 (NOT 0!). (When you do this, your background layer will be changed to “Raster 1″ or something similar.)

You can leave the file as is now, or you can add a watermark. Duplicate the sculptmap layer, switch it to 100% opacity and cut out your logo or text.

Now re-save your sculpt map in PNG format. Upload into Second Life.

TGA Format

Typically, in Photoshop, I like working with TGA alpha channels, just because you can retain all the color information in your image, even when pixels are completely transparent. The problem is that, in PSP, I have yet to find an easy way of viewing the alpha channel once one has been created, which makes things frustrating.

However, if you’d still like to use the TGA file format, here’s how.

Open your sculpt map. In order for this method to work, you need to select at least one pixel in your image. Do this however you want. The area you select will be visible in SL, so don’t select everything.  A neat idea would be to select an area shaped like your logo.

Next, go to the top menu and click on Selections > Load/Save Selection > Save Selection to Alpha Channel. PSP will give you a dialog, but the default settings should be fine. Hit Save.

Now go to File > Save As and save the sculpt map in TrueVision Targe (TGA) format. You may get a warning about only saving one alpha channel. Click Okay.

Now upload the sculpt map into Second Life. Part of the sculpt map will still be visible (the area you selected), but it won’t be enough information for anyone to steal your sculpt by the screenshot method.

Alpha in The GIMP

To add alpha protection to your sculpt map in GIMP, you can use the TGA or PNG formats.  Both formats work nearly the same.

PNG and TGA Formats

Open you sculpt map in Gimp, then open the Layers and Channels dialogs by going to the image menu and selecting Windows > Dockable Dialogs > Layers and Windows > Dockable Dialogs > Channels.

Now select Layer > Mask > Add Layer Mask.  You’ll get a dialog that asks what you want the layer mask to look like.  For now, tell it to give you a completely black mask.  Hit Add.  Now you’re layers dialog will look something like the image on the left

This new mask is completely black, which will make our sculpt map completely transparent.  If you’d like, you can use this mask as-is, but I’ll run you through an optional step to add a watermark to the sculpt map.

Open up your logo or watermark file, select it (CTRL-A) and copy it (CTRL-C).  Now in your layers dialog select the layer mask (NOT the layer itself!) and paste your logo (CTRL-V).

At this point, you will see the watermark on the sculpt map in the image window, but the selection will still be ‘floating’ in the layer dialog.

Right-click on this floating selection and select “Anchor Layer”.  This will de-float the selection, and you should see your watermark as the layer’s mask.

Finally, right click the layer mask and select “Apply Layer Mask.”  Your layer mask will disappear from the layer dialog, and be added as a fourth channel called Alpha, which you will see in the channels dialog.

Now you’re ready to save your sculpt map as either a TGA or a PNG file.  Oddly enough, this is the only step that’s different for the two file types.

For TGA files, you only have to save the image. It will bring up a small dialog, but it doesn’t matter whether or not you use RLE compression, as SL will re-compress the image anyway.

For PNG files, you’ll be presented with a larger dialog.  There are two options that you should pay attention to.

Find “Save Background Color” and un-check it.

Find “Save color values from transparent pixels.”  This is usually checked by default, but just make sure that it is.

The rest of the default values should work fine.  Press Save.

You’re finished! Upload your protected sculpt map into Second Life.