A dumb question, but frustrating. I want to load an existing texture into my A channel and one into the B channel for an AB blend. But every Mat I open pops up in the A channel-- never can put it into B. . .what am I doing wrong?

Try ctrl-clicking the B channel marker to place a marker in both the A and B channel.

I can do that-- the trouble is when I want to load an existing texture into the B slot, it pops up in the A slot instead. . .meaning that I can't blend between two textures that already exist in my Mat library. I believe that problem is that I'm confusing textures and Materials. . .loading a material seems to change all the texture slots, even if it only has one texture itself

Ah no you can't do it that way. Materials are everything in the material lab thus when you load one it replaces all the settings that you had before loading it. You have to adjust each channel seperately. To blend the materials you would have to note/write down each element that is part of that material and then apply it to one of the channels. The draw back to this is materials which use multiple channels will not be easily done. BTW each channel is a texture that is blended together to form a material.

This only works if each of the two materials you plan to use, uses only one channel. First, bring up the first material you plan to use in DTE and while holding the mouse curser over the components name and simultaneously holding down the shift key, click on the component name. This brings up the materials library. Save your first material here. Now do the same with your second material of choice and save that to the library as well. Now when you go to compose your new material using the two saved materials, put beads in the A and B channel pits. On each material that automatically appears again holding the mouse over the component name and holding down the shift key, bring up the materials library and select the first material you saved. Do the same with the B channel, bring in your second saved material and your set for business.

Good tip Quest! A lot easier than writing it down :)

That's exactly what I was trying to do. . .that tip is a keeper!

Thanks Quest that's good to know. 8)

Oh, man! Where were you months ago when I posed this question!

Don't forget, you can now substitute a saved material in the materials library for any number of channels to play with even using the same material more than once and intermingling with 2D textures. Sorry Nuke, I must have missed that post. Well, I'm sure it'll come in handy for future use.