View Full Version : Need help blending bump maps together

08-22-2006, 08:38 AM

I'm texturing a character I've modelled and am having trouble with blending different bump maps in the node editor.

I've created 4 different UV maps which deal with different parts of the character (they can't be consolidated into one because they need to overlap)

okay, so for the colour texture, I've created four 2d image nodes that use a different image each with their respective UV map.
In order that each image doesn't overlay another image in the wrong area, I've used weightmaps to control their transparency's. (the last one is not a weight it's another image).

ALL THIS WORKS FINE... the images blend correctly and don't appear in areas where they are told to be transparent.

This doesn't work the same for the bump layer. In the image attached, you'll see the colour texture nodes above (these are not connected to the surface for this test). And the bump nodes are down the bottom.

In the left section, I've shown that if I don't interconnect the the bump nodes, all that I get is the last texture showing through (even though the colours are connected) - this is kind of as expected.
In the right section, I've interconnected the bump nodes but you can see that the head bump has all the different bumps overlayed on it.. they are not paying attention to the transparency settings like the colour connectors do.

SO.... how can I achieve this if I can't do it this way.

Any suggestions would be apreciated.


08-22-2006, 08:52 AM
Just a quick image to show how seamlessly it actually works with the Colour texture...

this is without bump.. only colour texture is connected.


08-22-2006, 09:08 AM
As far as I know the bump-amplitude is NOT affected by the image opacity.
So you'd either have to plug the bump outputs into a vector-scale node, with the weightmaps (or whatever) plugged in the scalar amount, or you could plug the weightmap directly into the bump-amplitude input of your textures.
Now I can't exactly tell if you did that in your nodetree, because the node going to your bump-amplitude connections is hidden. ;)
But I hope I could help you :D

08-22-2006, 09:08 AM
Yes....!!... I figured it out.
I've posted an image below of a way to do it. While I don't think it's the most user friendly way to achieve it... it isn't convoluted and is pretty logical (just not consistent with how it's possible with colour).

instead of plugging in the alpha information into opacity, I've plugged it into bump amplitude.. that means the when something is supposed to be invisible, it has a bump amplitude of 0, etc. I've then multipliead each one by a single integer so I can control the max amplitude from that one integer.


ps. it's shown with colour and bump.. the flat area on the stomach is just because I haven't finished making that bump texture.

08-22-2006, 09:09 AM
I had problems with this in Surface Editor and RJJ from IFW2 told me to change the layers from "Normal" to "Additive" and it worked fine. It seems in 9.0 Normal cancels out previous layer unlike 8.5. But additive in Bump works great. The first layer can be Normal but layers above have to be additive,etc. Hopefully this will work for Node Editor.

08-22-2006, 09:11 AM
hey.. thanks Pomfried... I figured it out a few minutes before you posted... thanks for the info though.. it's not what I had done initially, I'd plugged just an integer into the bump amp.