PDA

View Full Version : Texture Layers in Bump Channel



automan25
12-16-2004, 11:28 AM
Hi All,

I'm having a really difficult time figuring out how texture layers react with each other in the bump channel. What appears to work in the color channel becomes completely different when placed in the bump channel.

For example, currently I have have two UV textures in the bump channel for a surface I'm working on. The texture at the bottom of the stack represents the bump pattern that I want to achieve on my surface. The texture above is a mask that is set up with the Alpha blending mode. Now in my mind the top texture should allow the texture below it to show through only at the points where white pixels exist in the mask, and not at all where the black pixels exist. In the final render the areas where there are black on the mask should be flat with no bump at all, and the white areas should allow the bump texture to come through.

As you can probably guess, this is not what's happening. As shown in the third image, the alpha mask isn't behaving as it normally would in the color channel. Instead the underlying texture comes through completely with the alpha mask only having a vague effect on it.

Any Ideas?

Silkrooster
12-16-2004, 05:56 PM
Were you trying to create raised lettering like the attached image?
Silk

automan25
12-16-2004, 07:19 PM
Well, recessed lettering actually, but yea, essentially the same concept you're showing there.

Silkrooster
12-16-2004, 08:13 PM
Just change the blending mode to subtractive then. That is assuming you are using white text with black background.
Silk

automan25
12-17-2004, 07:57 AM
I'll give that a shot. Have you ever gotten the Alpha blending mode to work properly in the bump channel though?

Silkrooster
12-17-2004, 05:53 PM
No I haven't actually I don't see where it helps all that much in the color channel either. I have tried an image with and without an alpha. But then again alphas in lightwave don't seam to behave like you would expect them to anyways. I guess the best bet when working on bumps is to stick with normal, add and subtract blending modes, atleast for now. If you read the manual, it should behave like you wanted it to. But for me the image is blended too much just like using an image with a grayscale from 40-60% shades of grey.
Silk