"omniverse" <omn### [at] charternet> wrote:
> "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> That object to mesh stuff is fascinating, unfortunately I'm terrible with
> meshes. And not so good with isosurfaces either. LOL
>
> Looks like you got a fair result. When I tried the in-pov converting from Chris
> Young I was getting inner CSG surfaces found until changing from unions to
> merge. Something I hadn't expected. No idea what could happen with isosurfaces
> based on that.
>
> Wish you luck.
>
> Bob

Thanks

I meshed this shape with different settings for resolution. The values are shown
under each example.

isoSmooth was set to no. The failures seem to happen regardless but this gives
an indication that in the first example, with resolution = 5, the failure is due
to the curvature being too tight.

However some of the higher settings of resolution gave what looks like meshing
failure.

Also flat is about 2.5 times faster.

(The meshing time is approximately proportional to the fourth power of the
resolution.)


http://news.povray.org/web.5846a1f84d513ebce15d43a80@news.povray.org

Post a reply to this message

"John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> "omniverse" <omn### [at] charternet> wrote:
> > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > That object to mesh stuff is fascinating, unfortunately I'm terrible with
> > meshes. And not so good with isosurfaces either. LOL
> >
> > Looks like you got a fair result. When I tried the in-pov converting from Chris
> > Young I was getting inner CSG surfaces found until changing from unions to
> > merge. Something I hadn't expected. No idea what could happen with isosurfaces
> > based on that.
> >
> > Wish you luck.
> >
> > Bob
>
> Thanks
>
> I meshed this shape with different settings for resolution. The values are shown
> under each example.
>
> isoSmooth was set to no. The failures seem to happen regardless but this gives
> an indication that in the first example, with resolution = 5, the failure is due
> to the curvature being too tight.
>
> However some of the higher settings of resolution gave what looks like meshing
> failure.
>
> Also flat is about 2.5 times faster.
>
> (The meshing time is approximately proportional to the fourth power of the
> resolution.)
>
>
> http://news.povray.org/web.5846a1f84d513ebce15d43a80@news.povray.org

Have you tried to set the recursion depth to 0 ?

Like this:

#declare Depth = 0;


I'm not able to see if the triangles are missing or if they are just dark. Can
you "see" through the openings where the triangles seem to be missing ?

--
Tor Olav
http://subcube.com

Post a reply to this message

"John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
>
> >> can my function, which is a single closed surface, be turned into mesh?
> >
> > Perhaps you can find something useful in this thread:
> >
> > Subject: Isosurface Approximation macros rewrite
> > From: Tor Olav Kristensen
> > Date: 2008 February 22nd
> > Message: <47be20ab@news.povray.org>
> > Newsgroup: povray.binaries.scene-files
> >
> >
http://news.povray.org/povray.binaries.scene-files/thread/%3C47cc76fd@news.povray.org%3E/
> >
> > --
> > Tor Olav
> > http://subcube.com
>
> I have had a look and am floundering.
>
> An example would be worth ten thousand words.
>
> Could some kind person point me at an actual example of converting a simple
> function, such as:
>     function(x,y,z){sqrt(pow(x,2)+pow(y,2)+pow(z,2))-L)/r }
> into a mesh object?

You can make any POV object into a mesh using trace.
My Rounded Prisms makes a Mesh2 file. Its at
http://leroywhetstone.s5.com/Pages/PovFiles.html#Tools

Although it's not simple, The basic idea is.
You take a mesh(in my case a simple flat surface) put the points into an array
then trace each point and save the new mesh.

Post a reply to this message

"Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > "omniverse" <omn### [at] charternet> wrote:
> > > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:

> > I meshed this shape with different settings for resolution. The values are shown
> > under each example.
> >
> > isoSmooth was set to no. The failures seem to happen regardless but this gives
> > an indication that in the first example, with resolution = 5, the failure is due
> > to the curvature being too tight.
> >
> > However some of the higher settings of resolution gave what looks like meshing
> > failure.
> >
> > Also flat is about 2.5 times faster.
> >
> > (The meshing time is approximately proportional to the fourth power of the
> > resolution.)
> >
> >
> > http://news.povray.org/web.5846a1f84d513ebce15d43a80@news.povray.org
>
> Have you tried to set the recursion depth to 0 ?
>
> Like this:
>
> #declare Depth = 0;

I have just tried this and the results are like a Picasso version of
Frankenstein's monster.

> I'm not able to see if the triangles are missing or if they are just dark. Can
> you "see" through the openings where the triangles seem to be missing ?

Yes they do seem to be missing and you can see through the holes. I have posted
an example to follow the last one

Post a reply to this message

"Leroy" <whe### [at] gmailcom> wrote:
> "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:

> > >> can my function, which is a single closed surface, be turned into mesh?

> You can make any POV object into a mesh using trace.
> My Rounded Prisms makes a Mesh2 file. Its at
> http://leroywhetstone.s5.com/Pages/PovFiles.html#Tools
>
> Although it's not simple, The basic idea is.
> You take a mesh(in my case a simple flat surface) put the points into an array
> then trace each point and save the new mesh.

Interesting... a very limited case mesher, but I think what is needed is a
simple-to-use meshing engine.

Post a reply to this message

"John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
....
> > Have you tried to set the recursion depth to 0 ?
> >
> > Like this:
> >
> > #declare Depth = 0;
>
> I have just tried this and the results are like a Picasso version of
> Frankenstein's monster.

IIRC the resolution has to be raised considerable if you have no recursion.


> > I'm not able to see if the triangles are missing or if they are just dark. Can
> > you "see" through the openings where the triangles seem to be missing ?
>
> Yes they do seem to be missing and you can see through the holes. I have posted
> an example to follow the last one

Ok. I see.

I think that using recursion may lead to unwanted holes.


--
Tor Olav
http://subcube.com

Post a reply to this message

"Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> ....
> > > Have you tried to set the recursion depth to 0 ?

> IIRC the resolution has to be raised considerable if you have no recursion.

> I think that using recursion may lead to unwanted holes.

This seems to work. With resolution = 50 and depth =0, the result was similar in
smoothness to resolution = 8 and depth =1 and the time taken was about the same.

And no sign of gaps so far.

Incidently, I see that the object is mesh and not mesh2. I thought I had seen
something about an improvement to this meshing programme that produced a mesh2
and was faster?

Thanks for the help.

John

Post a reply to this message

"John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > ....
> > > > Have you tried to set the recursion depth to 0 ?
>
> > IIRC the resolution has to be raised considerable if you have no recursion.
>
> > I think that using recursion may lead to unwanted holes.
>
> This seems to work. With resolution = 50 and depth =0, the result was similar in
> smoothness to resolution = 8 and depth =1 and the time taken was about the same.
>
> And no sign of gaps so far.

Good :)


> Incidently, I see that the object is mesh and not mesh2. I thought I had seen
> something about an improvement to this meshing programme that produced a mesh2
> and was faster?

Warp once made a program that can compress triangle meshes, but I don't remember
exactly what it can do. The latest version I can find mentioned is v3.0. It is
mentioned here:

http://www.povcomp.com/entries/46.php

I've tried to search for it, but with no luck so far. Perhaps someone else in
here knows where to find it. If not, you can just ask Warp.


> Thanks for the help.

No problem.


--
Tor Olav
http://subcube.com

Post a reply to this message

"John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > ....
> > > > Have you tried to set the recursion depth to 0 ?
>
> > IIRC the resolution has to be raised considerable if you have no recursion.
>
> > I think that using recursion may lead to unwanted holes.
>
> This seems to work. With resolution = 50 and depth =0, the result was similar in
> smoothness to resolution = 8 and depth =1 and the time taken was about the same.
>
> And no sign of gaps so far.

It would be interesting to see that head rendered as a mesh without holes at
that resolution or higher. (I'm curious about how much "noise" there is around
the eyes and below the nose.)

--
Tor Olav
http://subcube.com

Post a reply to this message

"Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > > "John Greenwood" <joh### [at] john-greenwoodcouk> wrote:
> > > > "Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:
> > > ....
> > > > > Have you tried to set the recursion depth to 0 ?
> >
> > > IIRC the resolution has to be raised considerable if you have no recursion.
> >
> > > I think that using recursion may lead to unwanted holes.
> >
> > This seems to work. With resolution = 50 and depth =0, the result was similar in
> > smoothness to resolution = 8 and depth =1 and the time taken was about the same.
> >
> > And no sign of gaps so far.
>
> It would be interesting to see that head rendered as a mesh without holes at
> that resolution or higher. (I'm curious about how much "noise" there is around
> the eyes and below the nose.)

I have posted an image at:
http://news.povray.org/web.584d34e77f9527eae15d43a80@news.povray.org
along with the source code. The noise around the eyes looks a bit like wrinkles!

John

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