I am working on making the paint macro able to use eval_pigment() instead  
of declaring a colour beforehand. Now I am able to render a complete scene  
this way. I first make a normal render of the scene without paint. Then I  
#declare that image as an image map on a z-plane so that it fits nicely in  
front of the scene, using it only to trace the colours. then I use the  
same direction vector to trace onto the scene and this is what I got.

Comments and suggestions welcome.
-- 
-Nekar Xenos-

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Attachments:
Download 'artists - copy (4).png' (942 KB) Download 'artists - copy (3).png' (934 KB)

Preview of image 'artists - copy (4).png'

Preview of image 'artists - copy (3).png'

I think this is a great way to make painterly renders. A whole new 
method to re-interpret POV-Ray scenes... without getting one's hands 
dirty ;-)

Thomas

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"Nekar Xenos" <nek### [at] gmailcom> wrote:
> I am working on making the paint macro able to use eval_pigment() instead
> of declaring a colour beforehand. Now I am able to render a complete scene
> this way. I first make a normal render of the scene without paint. Then I
> #declare that image as an image map on a z-plane so that it fits nicely in
> front of the scene, using it only to trace the colours. then I use the
> same direction vector to trace onto the scene and this is what I got.
>
> Comments and suggestions welcome.
> --
> -Nekar Xenos-

Great idea, have you tried making the blobs thinner in the x scale or longer in
the y to make it look more like a brush stroke?

This has given me a good idea for my moss placement, the shape of each clump of
moss was a bit square for my liking (as I just used trace over a rectangular
area), didn't think about using an image to place the moss. I will give that a
go.

Sean

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>Nekar Xenos  on date 13/05/2013 7.31 wrote:
> I am working on making the paint macro able to use eval_pigment()
> instead of declaring a colour beforehand. Now I am able to render a
> complete scene this way. I first make a normal render of the scene
> without paint. Then I #declare that image as an image map on a z-plane
> so that it fits nicely in front of the scene, using it only to trace the
> colours. then I use the same direction vector to trace onto the scene
> and this is what I got.
>
> Comments and suggestions welcome.
Wow, it's really impressive!
Perhaps you can use a mean value when the color change, in order to 
obtain smooth transitions.
Paolo

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"Nekar Xenos" <nek### [at] gmailcom> wrote:
> I am working on making the paint macro able to use eval_pigment() instead
> of declaring a colour beforehand. Now I am able to render a complete scene
> this way.

This is a *really* interesting technique that you're developing. (I've been
curious to see what you might come up with, as a logical extension of your
blob-men renders.) You've managed to turn the '3D-painting' problem completely
around, and come up with a nice workable technique. Well done!

I've been giving some thought to an idea: a built-in POV-ray 'tool' that uses a
greatly-modified combination of trace and eval_pigment, to actually find the
color that has *already been applied* to an object in 3-D space. I can see all
sorts of uses for such a tool--like placing correctly-colored paint blobs on an
object's surface!

Currently, eval_pigment can only be fed a *pigment* (obviously) to work
with--disconnected from any object that it might be applied to. While that's a
very useful tool, it naturally has limitations. This new idea would be to 1)
find an object's surface in space; and 2) evaluate the color at a point there.
(My conception of this trick would probably require no less than a 'ray tracer
within a ray tracer' to pull off successfully; but I think the 'ingregients' for
the tool already exist in POV-Ray.) Of course, there are lots of details that
such a scheme would have to deal with-- 'modifications' to the base pigment such
as lighting, highlites, radiosity, reflection, transparency, etc. that combine
to create the visible color.

But it need not be that complicated. In essence, a tool for finding just the
unmodified color at a point on an object's surface, nothing more.

But the idea might be doomed from the start--based on how ray-tracing works in
general: Finding the point of color (doing the 'ray trace') would probably be
done during the 'rendering' stage, with the result then having to be fed back
into the 'parsing' stage to be worked with. That might not be possible in
POV-Ray.

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Kenneth wrote:
> (My conception of this trick would probably require no less than a 'ray tracer
> within a ray tracer' to pull off successfully; but I think the 'ingregients' for
> the tool already exist in POV-Ray.)
Hi Kenneth,

Not sure if you have seen this before... Is something like this what you 
are talking about.

http://www.povray.org/documentation/view/3.6.2/124/

Sean

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Two suggestions:

It looks like the blobs need a more 'randomized' geometry, to give the
impression of a more natural 'painting technique.' As-is, they look a little bit
like simple flattened spheres.

The scene could probably use a less-extreme lighting set-up--not such deep
shadows--so that the colors are more in keeping with a 'painter's color
palette.' Perhaps just the addition of more ambient lighting would do that.

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> I am working on making the paint macro able to use eval_pigment()
> instead of declaring a colour beforehand. Now I am able to render a
> complete scene this way. I first make a normal render of the scene
> without paint. Then I #declare that image as an image map on a z-plane
> so that it fits nicely in front of the scene, using it only to trace the
> colours. then I use the same direction vector to trace onto the scene
> and this is what I got.
>

   The idea is really good, brilliant I would say... truly following the 
"twisted thinking" POV-Ray tradition. This specific usage is very 
interesting too: scary and surrealist.

--
Jaime

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On Mon, 13 May 2013 09:04:53 +0200, Thomas de Groot <tho### [at] degrootorg>  
wrote:

> I think this is a great way to make painterly renders.

That's the idea!
=)

> A whole new method to re-interpret POV-Ray scenes... without getting  
> one's hands dirty ;-)
>
> Thomas
>

I still do the real thing though ...

  :)

-- 
-Nekar Xenos-

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On Mon, 13 May 2013 09:40:23 +0200, s.day <s.d### [at] uelacuk> wrote:


> Great idea, have you tried making the blobs thinner in the x scale or  
> longer in
> the y to make it look more like a brush stroke?

Yes, I am busy with something like that. I keep tracing more blobs in the  
specified direction plus a bit of randomness, but at the moment it tends  
to look like a scene from The Thing
=8'S

> This has given me a good idea for my moss placement, the shape of each  
> clump of
> moss was a bit square for my liking (as I just used trace over a  
> rectangular
> area), didn't think about using an image to place the moss. I will give  
> that a
> go.

How about an L-system with random branches?
I've never had much success with L-Systems though.

-- 
-Nekar Xenos-

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