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rasputin

Derivative Maps? Concavity? Curvature?

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Hey guys,

I have been experimenting with the third-party software KNALD,    which takes your Color bitmaps...   and makes quite a few supporting texture maps from them.   The expected ones,  like Normal,  AO and Height,   but also things like a Derivative Map,   Concavity Map,  Convexity Map,  Curvature Map,  and a strange one called Transmission Map.  (See samples below:)

What are these extra maps for,    what do they do to a Material,     and do they have any usefulness within C4D?

It very much looks to me like a "Derivative" Map... is simply a color inversion of a Normal Map?     If so,  how would you use it?

Thanks,    ras

Derivative Map:
metal_rusted_2_KNALD_derivativeSM.thumb.png.3b6da837e22d4c43d76a536f6c882b22.png

Curvature Map:
1792007935_metalrusted2_KNALD_curvatureSM.thumb.png.2bacedc01e1e13b5ca54c6919aac9d9e.png


Convexity Map:
1809601279_metalrusted2_KNALD_convexitySM.thumb.png.ce397f37fbd4bea6fd7710a34a019066.png

Concavity Map:

1970251573_metalrusted2_KNALD_concavitySM.thumb.png.fdf984ab2c5d6c7fe5e531bd3fa1f3e0.png

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Curvature maps, or shaders, etc. are very nice for stuff like smudging or landscape setups, think of erosion etc. . One problem with these is that there exists a patent for curvature shaders that makes it hard for other comapnies to provide the functionality. i.E., R20 offers a ray tracing node that makes it possible to create a bevel shader (which is a special variation of a curvature shader), but MAXON can not build such a shader into C4D directly.

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You could possibly use the Concavity map for faking ambient occlusion?  Not sure.  What does the Transmission map look like?  To me that would be light transmission through the material, like a leaf.  With the texture you have here, which looks like a plaster wall or something, it should be all black.  I'm not sure how a program could determine that from a single image anyhow.  Maybe it's something else?

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  • 5 hours ago, natevplas said:

    What does the Transmission map look like?  To me that would be light transmission through the material, like a leaf. 

    Here's a Transmission map that KNALD created from a custom mesh that I had imported into it.    It very much looks like it's kind of an AO map on a macro scale?     Showing where light falls and misses on the mesh object,  but on an overall "shape" scale,   not on a textural scale?    ie.,  not getting onto tiny textural nooks-and-crannies,    just showing overall patterns of darkness and light?

    I do see that it's not an "Emission" Map,   which,  as you know,  is all about an object that glows.

    2030679992_metalbrasstarnisheddark_transmission.thumb.png.d563c3604884defcd59705f80c0c4891.png

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    Hmm, weird

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    On 10/4/2018 at 2:08 PM, srek said:

    Curvature maps, or shaders, etc. are very nice for stuff like smudging or landscape setups, think of erosion etc. . One problem with these is that there exists a patent for curvature shaders that makes it hard for other comapnies to provide the functionality. i.E., R20 offers a ray tracing node that makes it possible to create a bevel shader (which is a special variation of a curvature shader), but MAXON can not build such a shader into C4D directly.

    Hi Srek! Glad that you are still around here. :-) Any hint onwhere I can read about the functionality of this "bevel shader" to read about it and then to try to implement it with the nodesystem in R20 for my own purpose?

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    Sorry, i don‘t have that ready anywhere

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