Reuben Pearse <reu### [at] pearsecouk> wrote:
> Hi everyone,
>
> Is there a way to convert POV-Ray's internal representation of a 3D
> shape (i.e. one constructed using CSG) into another 3D format - perhaps
> mesh or mesh2?
>
> Would it possible to write a POV-Ray macro to scan the surface of an
> object and create mesh2 type co-ordinates (would the trace function be
> able to do this?)
>
> I'm just thinking it would be nice to be able to easily convert POV-Ray
> models to other formats :-)
>
> Thanks in advance
>
> Reuben
> reu### [at] pearsecouk

The relationship between the next link and this thread can be considered as very
subtle (at best), but can serve as inspiration to try another ways. I regret the
absence of more examples and the presence of syntactic and grammatical errors.

regards,
B. Gimeno

http://www.persistencia.org/CATHELP/CAT.html

Post a reply to this message

"B. Gimeno" <bgi### [at] lycoses> wrote:

>
> The relationship between the next link and this thread can be considered as very
> subtle (at best), but can serve as inspiration to try another ways. I regret the
> absence of more examples and the presence of syntactic and grammatical errors.
>
> regards,
> B. Gimeno
>
> http://www.persistencia.org/CATHELP/CAT.html

Thanks for the link!
That cubic golfer guy looks quite cool and inspiring. I'll give this a try when
I have some time again to do some POV-Ray experiments :)
Does this warning "VERY VERY VERY IMPORTANT: Ignore or forget this section will
dramatically raise up the parsing time without obtain results" refer to section
5 or to section 5.1 ?

Best wishes,

Simone

Post a reply to this message

> Does this warning "VERY VERY VERY IMPORTANT: Ignore or forget this section 
> will
> dramatically raise up the parsing time without obtain results" refer to 
> section
> 5 or to section 5.1 ?

To Section 5. The inclusion of the keyword "inside_vector" is well 
peremptory, without which the process is perpetuated without result. Thanks 
for your comment.
Soon, Mr. Cubic will be published at a higher resolution on your favorite 
news server.

B. Gimeno

P.D. That you look like a man playing golf is a Poserguy playing in a 
Discobolo pose being misunderstood by my macro, with several boxes aligned 
to the vector determined by vector_inside

Post a reply to this message

>> Does this warning "VERY VERY VERY IMPORTANT: Ignore or forget this section
>> will
>> dramatically raise up the parsing time without obtain results" refer to
>> section
>> 5 or to section 5.1 ?
>
> To Section 5. The inclusion of the keyword "inside_vector" is well
> peremptory, without which the process is perpetuated without result. Thanks
> for your comment.
> Soon, Mr. Cubic will be published at a higher resolution on your favorite
> news server.
>
> B. Gimeno
>
> P.D. That you look like a man playing golf is a Poserguy playing in a
> Discobolo pose being misunderstood by my macro, with several boxes aligned
> to the vector determined by vector_inside
>
>

In that case, try changing the orientation of the inside vector.
If it was "inside_vector x" change to "inside_vector <1,0.1,0.1>"

The cause of your problem is probably that the inside_vector is parallel 
to some triangle of the mesh.


Alain

Post a reply to this message

Marching triangles isn't the same as marching cubes I assume? I'm not able to
find much on marching triangles. I was thinking about trying to implement the
marching cube algorithm.

Post a reply to this message

jhu <nomail@nomail> wrote:
> Marching triangles isn't the same as marching cubes I assume?

  No. Marching cubes is much simpler, but produces significantly poorer
results (does not take into account the curvature of the surface in order
to dynamically produce more triangles in high-curvature areas, which means
that it often misses smaller details, and it often produces extremely thin
triangles which may cause problems).

  The marching cubes algorithm also has a negative fame because some idiot
patented it on the US. (The patent might be expired by now.)

-- 
                                                          - Warp

Post a reply to this message

On Sat, 20 Mar 2010 12:41:15 -0300, Warp <war### [at] tagpovrayorg> wrote:

>   The marching cubes algorithm also has a negative fame because some  
> idiot
> patented it on the US. (The patent might be expired by now.)
>

Yes, the marching cubes patent expired in 2005.

Hugo.

Post a reply to this message

Le 20/03/2010 18:41, Hugo nous fit lire :
> On Sat, 20 Mar 2010 12:41:15 -0300, Warp <war### [at] tagpovrayorg> wrote:
> 
>>   The marching cubes algorithm also has a negative fame because some
>> idiot
>> patented it on the US. (The patent might be expired by now.)
>>
> 
> Yes, the marching cubes patent expired in 2005.
> 
That's a good news. I had patches of 3.1g which used marching cube to
tesselate solid object into mesh... with due restriction about import in
US zone.

Have you any accurate data (such as exact expiry date of marching cube ?)
(Gif was also troublesome)

Post a reply to this message

On Sat, 20 Mar 2010 22:08:09 +0100, Le_Forgeron <jgr### [at] freefr> wrote:
>
> Have you any accurate data (such as exact expiry date of marching cube ?)

http://www.google.com/patents/about?id=T1Q3AAAAEBAJ&dq=4710876
  or
http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F4710876

U.S. patents generally last up to 20 years.



-- 
FE

Post a reply to this message

Le_Forgeron <jgr### [at] freefr> wrote:
> Le 20/03/2010 18:41, Hugo nous fit lire :
> > On Sat, 20 Mar 2010 12:41:15 -0300, Warp <war### [at] tagpovrayorg> wrote:
> > 
> >>   The marching cubes algorithm also has a negative fame because some
> >> idiot
> >> patented it on the US. (The patent might be expired by now.)
> >>
> > 
> > Yes, the marching cubes patent expired in 2005.
> > 
> That's a good news. I had patches of 3.1g which used marching cube to
> tesselate solid object into mesh... with due restriction about import in
> US zone.

  I really think we should concentrate on the marching triangles algorithm
and forget about marching cubes. The latter, bluntly put, outright sucks as
a tesselation algorithm. The results are horrid.

-- 
                                                          - Warp

Post a reply to this message