I was just surfing the web when I came up with an idea on how to do patina
and metal wear.  Here it is:
You know how the find_edges post process filter compares the differences in
normal surface angles?  How about we use this in a pigment? Sort of a
combination of Find_edges and slope?  I if an angle is getting sharper, you
could put a shiny line there, and if it is getting shallower, put a dark
line.  Hmm.  Didn't quite explain it as well as I'd like.  Once more:

_|  <--- this angle would have a darker (or user defined) color at the
vertex.
_
  | <--- This angle would have a lighter or user-defined color at the
vertex.  

Perhaps you could apply a smoothing method of some sort to gradient the
line of color.  This strikes me as a extremely fast way to render patinas. 
This would be a God-send to all those realistic modlers out there.  Nathan,
Chris, is this a possible thing to do?

-- 
H.E. Day
<><

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Great idea.  I've tried the 'find_edges' on the sPatch vase model and it can
simulate a patina in a crude way already.
Have a look here: http://members.aol.com/wrld0rigin/vasepatina.jpg
I used settings of:

find_edges{
  .1, 1, .0075, 4, .01, gradient y
   color_map {[0 rgb <.5,1,.75>*.25][.25 rgb <.5,1,.75>*.67][.67 rgb
<.5,1,.75>*.75][1 rgb <.5,1,.75>*.33]}
}

over the copper-color texture which has a radial normal to accentuate the
surface for the find edges process to better apply.  Note that the highlights
are affected as well, the major problem is that this isn't confined to surface
normals (not 'normal') or rather the surface deformations without any external
influences such as lighting.  I'd think this may be just something Chris Huff
can do though  :-)

Bob

"H. E. Day" <Pov### [at] aolcom> wrote in message
news:01bfcf69$29d98460$6a7889d0@daysix...
| I was just surfing the web when I came up with an idea on how to do patina
| and metal wear.  Here it is:
| You know how the find_edges post process filter compares the differences in
| normal surface angles?  How about we use this in a pigment? Sort of a
| combination of Find_edges and slope?  I if an angle is getting sharper, you
| could put a shiny line there, and if it is getting shallower, put a dark
| line.  Hmm.  Didn't quite explain it as well as I'd like.  Once more:
|
| _|  <--- this angle would have a darker (or user defined) color at the
| vertex.
| _
|   | <--- This angle would have a lighter or user-defined color at the
| vertex.
|
| Perhaps you could apply a smoothing method of some sort to gradient the
| line of color.  This strikes me as a extremely fast way to render patinas.
| This would be a God-send to all those realistic modlers out there.  Nathan,
| Chris, is this a possible thing to do?
|
| --
| H.E. Day
| <><

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In article <01bfcf69$29d98460$6a7889d0@daysix>, "H. E. Day" 
<Pov### [at] aolcom> wrote:

> I was just surfing the web when I came up with an idea on how to do 
> patina and metal wear.  Here it is:
> You know how the find_edges post process filter compares the 
> differences in normal surface angles?  How about we use this in a 
> pigment? Sort of a combination of Find_edges and slope?  I if an 
> angle is getting sharper, you could put a shiny line there, and if it 
> is getting shallower, put a dark line.  Hmm.  Didn't quite explain it 
> as well as I'd like.  Once more:

This is similar to the way I tried to do it, except I implemented it as 
a pattern so you could use it as a pigment/texture map. Unfortunately, I 
never got good results...maybe I will make another try.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/

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