Hi,

 Is there any chance to get real 2D curves with this (modified,
 of course) post process? It can be very usable for creating
 hidden-lined drawings with POV.

Disnel

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In article <3A13D08F.ACC37273@hlavacek-partner.cz>, Disnel 
<dis### [at] hlavacek-partnercz> wrote:

>  Is there any chance to get real 2D curves with this (modified,
>  of course) post process? It can be very usable for creating
>  hidden-lined drawings with POV.

Could you clarify? I have no idea what you want...output of splines 
defining the edges? Or just constant-width lines?

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:
> 
> In article <3A13D08F.ACC37273@hlavacek-partner.cz>, Disnel
> <dis### [at] hlavacek-partnercz> wrote:
> 
> >  Is there any chance to get real 2D curves with this (modified,
> >  of course) post process? It can be very usable for creating
> >  hidden-lined drawings with POV.
> 
> Could you clarify? I have no idea what you want...output of splines
> defining the edges? Or just constant-width lines?

Yes, splines or polylines for example. Output to some vector oriented
format
(DXF, PS or just text file with some representation of splines)

> 
> --
> Christopher James Huff
> Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
> TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
> 
> <><

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Disnel wrote:
> 
> Yes, splines or polylines for example. Output to some vector oriented
> format
> (DXF, PS or just text file with some representation of splines)
> 
	Use the current output, then run it through autotrace:
http://homepages.go.com/homepages/m/a/r/martweb/AutoTrace.htm


-- 

* Abandon the search for truth, * mailto:ber### [at] inamecom
* Settle for a good fantasy.    * http://www.enst.fr/~jberger
*********************************

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In article <3A13E216.92046D4E@hlavacek-partner.cz>, Disnel 
<dis### [at] hlavacek-partnercz> wrote:

> Yes, splines or polylines for example. Output to some vector oriented 
> format (DXF, PS or just text file with some representation of 
> splines)

This would be extremely difficult, and would probably be best as a 
separate filter(so you can use it on any scene instead of only scenes 
using find_edges. This is a per-pixel filter, it does not generate 
splines internally and draw lines over the image, it takes each pixel 
and tries to decide whether it is on an "edge". I have no idea where to 
start converting the resulting pixel map into a group of splines...

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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> 
> This would be extremely difficult, and would probably be best as a
> separate filter(so you can use it on any scene instead of only scenes
> using find_edges. This is a per-pixel filter, it does not generate
> splines internally and draw lines over the image, it takes each pixel
> and tries to decide whether it is on an "edge".

Hmmm, you ansvered me.

> I have no idea where to
> start converting the resulting pixel map into a group of splines...
> 

How about use normal vector to surface and assing, that resulting
contour of object will be perpendicular to normal vector's projection
into image plane? (Just an idea, don't know, if I'am right). And
how about edge between two CSG objects?

Disnel

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In article <3A190F57.223A8EDF@hlavacek-partner.cz>, Disnel 
<dis### [at] hlavacek-partnercz> wrote:

> How about use normal vector to surface and assing, that resulting
> contour of object will be perpendicular to normal vector's projection
> into image plane? (Just an idea, don't know, if I'am right).

I have no idea what you are trying to say...


> And how about edge between two CSG objects?

CSG objects work the same as any other objects. Why should they be any 
different?

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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> > How about use normal vector to surface and assing, that resulting
> > contour of object will be perpendicular to normal vector's projection
> > into image plane? (Just an idea, don't know, if I'am right).
> 
> I have no idea what you are trying to say...

When you have sphere, for example, its controur is circle.
Normal vector to this circle is the same as projected normal
vector to sphere in this point. Thus we have direction of
sphere's controur in this point and we can search next point
in nearly that direction. This fails for edges on rotated cube,
for example (generally on all edges, it is usable for countour
of objects).

> CSG objects work the same as any other objects. Why should they be any
> different?
> 

And it fails also on edge between two parts of some CSG.

Disnel

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In article <3A1CE769.BDA52F38@hlavacek-partner.cz>, Disnel 
<dis### [at] hlavacek-partnercz> wrote:

Basically using the normal value of the pixels at an edge to determine 
where to look for the next pixel on the edge? I don't know how easy or 
reliable this would be...I think you would be better off doing the 
spline outlines by hand.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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> Basically using the normal value of the pixels at an edge to determine
> where to look for the next pixel on the edge?

Exactly.

> I don't know how easy or
> reliable this would be...

Just an idea ;-).

> I think you would be better off doing the
> spline outlines by hand.

Hmmm, its also one possible way to solve problem ;-).

Disnel

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