mib_color_mix being weird with bump

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  01 January 2013
mib_color_mix being weird with bump

I have 5 layers with their own exclusive weight maps made in PS.
By exclusive, I mean that where one contains a 1 value, all other maps have a 0 value.. where one has a .3 value, another may have .3, and another .4.. just to say that it always adds up to 1 by the way I've done it by inverting the layers and repositioning them above one another before saving out as IFFs.

Each of these maps goes into weights 0 to 4 in the mib_colour_mix node.
Their respective mia_material_x shaders are plugged into colours 0 to 4.
(The last one, Roads, is currently not added while I try to solve the current issues)

Num - 4

Mode 0 - mix
Mode 1 - add
Mode 2 - add
Mode 3 - add
Mode 4 - blend
Mode 5 - blend
Mode 6 - blend
Mode 7 - blend

Weight 0 - Road.iff
Weight 1 - Soil.iff
Weight 2 - Cliffs.iff
Weight 3 - Gravel.iff
Weight 4 - [black]
Weight 5 - [black]
Weight 6 - [black]
Weight 7 - [black]

Colour 0 - Road [Mia_Material_X's result]
Colour 1 - Soil [Mia_Material_X's result]
Colour 2 - Cliffs [Mia_Material_X's result]
Colour 3 - Gravel [Mia_Material_X's result]
Colour 4 - [black]
Colour 5 - [black]
Colour 6 - [black]
Colour 7 - [black]

Colour Base - Sand.iff

The mib_color_mix is plugged into the Material Shader and Shadow Shader attributes of the shading engine for my landscape's geometry.

Alpha is luminance is ticked on all shaders.

The Problem

Each of those Mia_material_X's has it's own pair of fractals going into a ramp with a sampler info node on the facing ratio, there's no issue there, all the shaders show these colours in their respectful locations based upon their weight maps as expected..

However.. they also have their own bump maps, simple 2D or 3D fractals, going into the 'standard bump' inputs of said materials, and these are not behaving correctly in so many ways.

Sand uses a 2D Noise for bump, and this bump is present on all layers after it, despite the weight maps of the following layers being over the top of it.
Road has an image map for part of the bump,
Soil uses a 2D Noise for bump, and this bump is present on all layers after it too, despite the fact that the weight map for that shader excludes those areas.
Cliffs has a image map, and its fractals on bump plugged into it appear in no other shaders.
Gravel uses a 2D Noise for bump, which is not present in any other shaders..

This has been driving me insane for days now, I've done every tutorial on this shader I can find, and it just doesn't work =/
All I want to do is have multiple shaders on the same model..

It doesn't make a difference if I use Mix or Blend, and any other modes just make it worse..
Does anyone have any idea what I'm doing wrong here?

Thanks for your time,

Last edited by dudeman38 : 01 January 2013 at 12:29 PM.
  01 January 2013
had the same problem some time ago and never find an answer, if you do, i will appreciate if you share your solution. good luck!!
  02 February 2013
I will test this later when I get some time but I'm thinking the only way to solve this or the only other way I could think of applying bump is through the old legacy bump nodes.

  02 February 2013
Well, I'm not 100% sure they're exclusive as it's terrain and I'm in a hurry now, but they're looking great after being placed in strategic order based on the possibility that some will override the lower (higher numbered) layers, so I put the more exclusive ones on top.. ensuring alpha is luminance is ticked and using the alpha gain everywhere i use the colour gain for any map seems to help but doesn't always exclude things as it should..
I'm in a hurry now to set a project rendering and jump on a plane, don't really have time to type this tbh, but i will soon link you here to a set-up of the basic network working correctly (as far as I know) when i have time
  02 February 2013
Masking each bump individually using the same maps you are using to blend the materials might work.
Demo Reel 2012-13!
  02 February 2013
Yeah funnily enough, it actually wasn't working that way lol.. weird, I know.. the values were going through the alpha and colour offsets of my weight maps before going to their shaders and then the mix..
  02 February 2013
Yeah I never tried with more than two materials but when I was using the two I used a multiply divide node and multiplied the bump map by the mask then put the result into the bump slot.

Also you can use blend colors, put the result of the Mia materials into the color, then use a map for the blend. You could probably string a few of those together, they work with the bumps I believe.
Demo Reel 2012-13!
  02 February 2013
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