I'm working on a procedural texture, and have run into a little trouble with the alpha channel. The basic idea is that the orange color will be highly reflective/specular/metallic, and the green stuff won't be (i.e. I'm making a dirty copper texture). As nearly as I can tell, the way this would be done would be to create an alpha channel for the image with white over the orange areas, and black over the green areas, then apply this to specularity, metallicity, and reflection. So, the question is: using the deep texture editor, how would I create such an alpha channel? How can I set up an alpha channel to be the inverse of component 2? Also, a peculiar behavior: even though no components are currently set to contribute to the alpha channel, the alpha channel is not blank. Where does this pattern come from?

To invert the alpha channel, drag the A and B numbers in the filter so that they switch with each other. For example, if A: 1 and B: 0, then the inverse is A:0 and B:1. You might also need to switch the sign (i.e negative 1) To work on the overall alpha channel, Click the "A" buttons for each of the components on the right side of each one (A=alpha, C=color, B=bump) and deselect B and C. This will show you the alpha of each one, and the component will also be displayed as a black and white map. In the filter window, click the top button furthest to the right to select the combination texture. Now play with the filter settings to see if you can do it that way. If not, shift-click the combination name and save your component. Then create a new component in the main materials window for specularity. Shift-click the name of this component and load your saved texture from the library. Now go into the edior and make the alpha for the 2nd component very dark in the filter window. Then make the alpha for component 1 very bright. THis should do it. This way you have the other texture driving the color, and a modified version driving the alpha.

If you have no alpha components enabled, bryce will just average all of them. I don't know why this is...

Hmm, my problem seems to be a lack of understanding of what the buttons do. I had thought that dimming the "A" button of a component would cause that component's alpha value to be ignored, but that doesn't appear to be the case. To work around this, I created a second texture with component one set to be the green portions of my texture and the other two components disabled. Working with the color selected, I was able to get the colors to invert properly by negating the "A" value (from 1 to ~ -1). Unchecking the "C" button to look at my alpha revealed a problem, however: The color circles along the side do not affect the alpha channel at all. You can see the problem this causes in the attached image: component 1, the color channel, has been modified to show what I want the alpha channel to look like. Component 2 shows the actual alpha channel... Many areas that should be masked out by the color selection are bright white. Attempts to raise or lower the overall color of the alpha by changing the filter graph resulted in "holes" in the mask (areas would become darker, black, then switch to white).

Okay, found a work around. Switched filter mode to "clip," and played around with it a bit. The end result is "close enough" for my purposes, but it is frustrating to have exactly what I want in the color channel, and no way to access it.