stbenge <THI### [at] hotmailcom> wrote:
> currently impossible to use any proximity patterns with meshes. That's
> right, impossible!

What are proximity patterns?  Is it like AO or radiosity?

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"Trevor G Quayle" <Tin### [at] hotmailcom> schreef in bericht 
news:web.493594d862d2e22181c811d20@news.povray.org...
>
> A *quick* render.  I have made it very shiny!
>
LOL

Now let that baby ROAR....

(and black smoke, please....)   :-)

Thomas

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nemesis wrote:
> stbenge <THI### [at] hotmailcom> wrote:
>> currently impossible to use any proximity patterns with meshes. That's
>> right, impossible!
> 
> What are proximity patterns?  Is it like AO or radiosity?

I'm not sure if the term "proximity pattern" ever existed before 
MegaPOV. I remember seeing it a long time ago as a new feature, but 
never got to play with it.

Basically a proximity pattern is like a gradient indicating the distance 
from a surface in 3D space. Imagine making an object pattern from some 
object and applying a 3D blur to it. What you get is a fuzzy 
representation of your object, but in pattern form. As a special bonus, 
the inside edges and vacations end up black, the outside edges and 
protrusions end up white, and all the flat parts in between end up a 
gray color.

I have created two versions which I use for different things. I have 
released one of them bundled with the fastSSS macros, but I think I will 
release another include with just the proximity macros.

Sam

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stbenge wrote:

> The biggest reason I didn't model this as a mesh is because it's 
> currently impossible to use any proximity patterns with meshes.

you never know when a wax tractor might come in handy ;)

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stbenge wrote:
> Basically a proximity pattern is like a gradient indicating the distance 
> from a surface in 3D space. Imagine making an object pattern from some 
> object and applying a 3D blur to it. What you get is a fuzzy 
> representation of your object, but in pattern form. As a special bonus, 
> the inside edges and vacations end up black, the outside edges and 
> protrusions end up white, and all the flat parts in between end up a 
> gray color.

Sounds like AO.  The occlusion effect is likewise achieved by taking 
into account surrounding geometry, not angle of incidence or position of 
light sources.  Your image looks very AO like.

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stbenge <THI### [at] hotmailcom> wrote:

> They are manually rounded off using cylinders, torii and spheres.
> There's an object pattern trick for making edges look rounded using
> surface normals, but it doesn't work too well with most objects.

Gosh.  I did that with a piano a few years back.  It was a *lot* of work and it
wasn't nearly this complex.  That's very impressive.

 - Ricky

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nemesis wrote:
> stbenge wrote:
>> Basically a proximity pattern is like a gradient indicating the 
>> distance from a surface in 3D space. Imagine making an object pattern 
>> from some object and applying a 3D blur to it. What you get is a fuzzy 
>> representation of your object, but in pattern form. As a special 
>> bonus, the inside edges and vacations end up black, the outside edges 
>> and protrusions end up white, and all the flat parts in between end up 
>> a gray color.
> 
> Sounds like AO.  The occlusion effect is likewise achieved by taking 
> into account surrounding geometry, not angle of incidence or position of 
> light sources.  Your image looks very AO like.

AO and proximity patterns give different results. Proximity patterns can 
give you access to *outside* edge data as well as inside edge data. AO 
just makes inside edges dark. Proximity patterns also make thin objects 
lighter in color, and thicker ones slightly darker. When I combine my 
proximity macros, I'll post examples to this group so you can see for 
yourself how it looks.

Sam

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triple_r wrote:
> Gosh.  I did that with a piano a few years back.  It was a *lot* of work and it
> wasn't nearly this complex.  That's very impressive.

It's time consuming, that's for sure :/

Sam

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stbenge <THI### [at] hotmailcom> wrote:
>
> The biggest reason I didn't model this as a mesh is because it's
> currently impossible to use any proximity patterns with meshes. That's
> right, impossible! Actually, if somebody can figure out how to get a
> proximity pattern working with meshes, I would really appreciate it :)

Just write your own inside() function. I gave it a go with the following, and it
seems to work pretty well. It should really be improved with the equivalent of
an inside_vector, so you can usefully use it with open meshes, but it's OK for
a quick attempt.

#macro inside_m( obj, pos )
 #local current = pos;
 #local dir = x;
 #local done = 0;
 #local num = 0;
 #while ( done != 1 )
  #local norm = <0,0,0>;
  #local inter = trace( obj, current, dir, norm );
  #if ( vlength( norm ) != 0 )
   #local num = num + 1;
   #local current = inter + <0.0001,0,0>;
  #else
   #local done = 1;
  #end
 #end
 (mod( num, 2 ) = 1)
#end

Cheers,
Edouard.

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Attachments:
Download 'fastprox_bunny.jpg' (19 KB)

Preview of image 'fastprox_bunny.jpg'

"Edouard Poor" <pov### [at] edouardinfo> wrote:
> stbenge <THI### [at] hotmailcom> wrote:
> >
> > The biggest reason I didn't model this as a mesh is because it's
> > currently impossible to use any proximity patterns with meshes. That's
> > right, impossible! Actually, if somebody can figure out how to get a
> > proximity pattern working with meshes, I would really appreciate it :)
>
> Just write your own inside() function. I gave it a go with the following, and it
> seems to work pretty well. It should really be improved with the equivalent of
> an inside_vector, so you can usefully use it with open meshes, but it's OK for
> a quick attempt.
>
> #macro inside_m( obj, pos )
>  #local current = pos;
>  #local dir = x;
>  #local done = 0;
>  #local num = 0;
>  #while ( done != 1 )
>   #local norm = <0,0,0>;
>   #local inter = trace( obj, current, dir, norm );
>   #if ( vlength( norm ) != 0 )
>    #local num = num + 1;
>    #local current = inter + <0.0001,0,0>;
>   #else
>    #local done = 1;
>   #end
>  #end
>  (mod( num, 2 ) = 1)
> #end
>
> Cheers,
> Edouard.

Forgive me for being slow as usual, but could you could help me understand your
macro?

I suppose you could used the inside test to fill up the inside of a mesh with
cubes to make CSG approximation of a mesh shape--but that doesn't appear to be
what you did.

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