It has been 10 days since we posted first version of pov-ray with
subdivision. The number of responses and downloads has been
certainly beyond our expectation. We are glad that if you found it useful.
All the feedback has positively motivated us to make it a better program.

Now we have the new version v0.02. It can be downloaded at the same place:
http://www.cise.ufl.edu/~xwu/Pov-Sub

You will want to have the new version if your scene

  i) contains complex meshes.
   -  The performance of the new version is drastically better. Objects
      that require minutes before now only take seconds!

 ii) has "mesh" objects.
    - The support for "mesh" has been added

iii) has objects with boundaries
   - The boundary can be dealt with in two ways now. The default gives
    a smooth curve on the boundary. Another option is to discard the
    triangles without enough neighbors.

Thanks!
Xiaobin Wu
xwu### [at] ciseufledu

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Dear all,

I want to create a gallery section on my page which
includes all sorts of images that are created using
subdivision surfaces.

If you are interested in posting your pictures, please kindly
send me URLs that links to your image. A pair of before/after
subdivision images will be great.  A link to your webpage
will be provided (unless you prefer not).

Thanks in advance, and happy ray-tracing. :)
Xiaobin

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"Xiaobin Wu" <xwu### [at] cisefuledu> wrote:
> It has been 10 days since we posted first version of pov-ray with
> ...

Thanks for your efforts. I am just a user, but I think it's a very cool idea
to stick this kind of feature inside Pov-Ray. I agree with another's
suggestion that an option to save the resulting mesh would useful.

Could we also get an ability to apply displacements and warps to the mesh
inside Pov-Ray as an extension to your current work? Many of the new
Pov-Ray 3.5 features greatly expand our ability to model on the fly with
Pov-Ray. Parametric objects, isosurfaces, sphere sweeps and the like - but
these features are often very slow.

I am aware of one package written in POV-Ray's SDL that can replace some of
these objects with meshes. It would be helpful to couple surface
subdivision / smoothing with this mesh replacement of complex objects
feature. All done inside Pov-Ray.

For example, I can envision creating water surfaces and such with an on the
fly mesh capability.

I suppose preventing dengenerate meshes in all cases could be difficult...

Oh, a small thing, the figure text for the right most figure of example 4 on
your web page should I think read "After 2-step subdivision."

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"Xiaobin Wu" <xwu### [at] cisefuledu> wrote in news:40aeaf37@news.povray.org:

> It has been 10 days since we posted first version of pov-ray with
> subdivision. The number of responses and downloads has been
> certainly beyond our expectation. We are glad that if you found it
> useful. All the feedback has positively motivated us to make it a
> better program. 

First of all kudos for your work on this POV-Ray patch.

I've some questions:
- When is subdivision performed? As a preprocessing step after parsing and 
before rendering (actually creating a new, more detailed, mesh/mesh2 
object and substituting the original object with the subdivided one) or 
dynamically from the original mesh/mesh2 at rendering time, without 
keeping in memory the subdivided one?

- I do not understand the new discard_boundary switch. It discards 
boundary edges that do not meet which conditions?

May I suggest to look at Wings (www.wings3d.com): it has an export plugin 
(http://www.midcoast.com.au/~rgcoy/software.html) that outputs models to 
POV-Ray (in various ways) and is able to perform the subdivision. Even if 
I think they adopt the Catmull-Clark with infinitely sharp creases scheme 
it may be useful to create test models, "grab" some great free models, 
look at the export plugin implementation (beware they use a new, strange 
scripting language called Erlang).

--
Alessandro Falappa

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Thanks a lot for your valuable input.

"William Pokorny" <pokorny_epix_net> wrote in message
> Thanks for your efforts. I am just a user, but I think it's a very cool
idea
> to stick this kind of feature inside Pov-Ray.
I think so too. But they haven't asked yet. ;-) Really, my guess is the
basic features
need to completed before they consider add it in. But since I can only work
on
this on my spare time, the process might take a while.

> I agree with another's suggestion that an option to save the resulting
mesh would useful.
ok, I will see what I can do. maybe a command like "export_mesh <filename>"
?

> Could we also get an ability to apply displacements and warps to the mesh
Sounds interesting. Is it the displacement mapping you want? (such as a 3-d
flower
print on a vase.)

> I am aware of one package written in POV-Ray's SDL that can replace some
of
> these objects with meshes. It would be helpful to couple surface
It is good to know this. If this exists, it will be easy to get subdivision
working
on other objects upon this package. I will look into the possibilitties.

best regards,
xiaobin

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"Alessandro Falappa" <don### [at] nessunoit> wrote in message
news:Xns94F37299C5667alexfalappa@203.29.75.35...
>
> - When is subdivision performed?
The subdivision is done at the end of parsing. And the new subdivided
mesh is kept in memory and ray-traced. Clearly this isn't the optimal
method,
due the memory reason, and the fact that pressing stop won't stop
the parsing process. On-the-fly method would have the advantages,
and again a nice thing to implement next. It will likely kill the
export_mesh option, though.

> - I do not understand the new discard_boundary switch. It discards
> boundary edges that do not meet which conditions?

It discards the new traingles that are on the boundary.
Take a look at figure 3 in the following paper by Bischoff etc.
http://www-i8.informatik.rwth-aachen.de/publications/downloads/loop_render.pdf
This is useful in some occasions, for example what I did in my euro-graphics
2004 paper
(visualizing the loop patches.)

best regards,
Xiaobin

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hi,

could you add a sort of "autosmooth" option
in such way that a vertex is smoothed only
if the normal value is below a threshold ?

-- 
@+
jms - http://jmsoler.free.fr

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jms wrote:

> hi,
> 
> could you add a sort of "autosmooth" option
> in such way that a vertex is smoothed only
> if the normal value is below a threshold ?
> 

Sorry : involuntary crossposting .

-- 
@+
jms - http://jmsoler.free.fr

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"jms" <jms### [at] domaininvalid> wrote in message
news:40c1924d$1@news.povray.org...
> hi,
>
> could you add a sort of "autosmooth" option
> in such way that a vertex is smoothed only
> if the normal value is below a threshold ?
>
If I understand correctly, you mean the automatically identification
of crease edges from normal directions. This feature will be included
in the next update(v0.03), this week or sometime next week.

Xiaobin



> -- 
> @+
> jms - http://jmsoler.free.fr
>
>
>

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