[Bf-committers] Curvature Input

[Roger Wickes]

To me, it seems like you would just take the difference between the two surface normals. I would use positive numbers for diverging vectors (hills), and negatives for converging (valleys), with some accommodation for unit-space density, since there are more faces/edges at creases (generally) to sculpt and define the surface, which is irrelevant in metal forming. 

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________________________________
From: Brecht Van Lommel <brecht at blender.org>
To: bf-blender developers <bf-committers at blender.org>
Sent: Thursday, December 25, 2008 3:51:40 AM
Subject: Re: [Bf-committers] Curvature Input

Hi,

Mathias Panzenböck wrote:
> Normals do not work because the effect is view vector independent and it
> distinguishes between "hill tops" and "valleys". But using a effect dependant on
> a x/y/z offset will obviously not work, because the surface is round. Its a
> bronze statue where there is corrosion in grooves and where there is shiny
> bronze otherwise.

Curvature is typically computed at edges, with the dot product between 
the normals of two adjacent faces. I don't think there is a way to get 
that kind of result with existing options.

>>     I'd like to make a material which color depends to the curvature of
>>     the surface
>>     of the mesh. I figured this would be much like the stress input
>>     option for
>>     texture coordinates. So my question is, at which files I'd have to
>>     look to add
>>     such an option?

You basically answered the question yourself, just find files with the 
  word "stress" in them and implement it similarly. It really would be 
exactly same code except for the function that actually computes the 
values.

Brecht.
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