i am going mad.
now only one part is not visible in mirror.
but it comes better:
back part of object is visible in mirror but not in front of it. then I rendered it
without the mirror.
and what should I say: it is invisible!

like Mike Williams said: watch max_gradient warnings.
this time I get one:
Shutdown Warning: The maximum gradient found was 1.001, but max_gradient of the
 isosurface was set to 2.038. Adjust max_gradient to get a faster rendering of
 the isosurface.

if max_gradient is set to 1.001 Povray warns that max_gradient found is 2.038 and vice
versa.

I don not know if this has something to do with my problem. but hints are welcome.

soon I post an image to p.b.images.

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difference{
object { isosurface1_containedby_box }
object {
isosurface2_containedby_box
translate y*-value
}
rotate x*90

double_illuminate
}

"marabou" <not### [at] availableyet> a écrit dans le message de
news:200### [at] availableyet...
> On Tue, 10 Oct 2006 17:25:02 +0200
> "Penelope20k" <pen### [at] caramailfr> wrote:
>
> > the 'what' you see in the mirror is not your iso surface ..i think its
the
> > reflects light of your isosurface ...
> > like difference { A B ..with no_reflection statement }
> >
> > i dont see also the shadow of your isosurface ...this is strange also
..(but
> > doenst count yet)
> [..]
>
> there is a shadow of isosurface in mirror. look between my painted lines.
there is a shadow from light on the ground. it ist a little bit blinded.

Post a reply to this message

marabou wrote:
> [...]
> like Mike Williams said: watch max_gradient warnings.
> this time I get one:
> Shutdown Warning: The maximum gradient found was 1.001, but
> max_gradient of the
>  isosurface was set to 2.038. Adjust max_gradient to get a faster
>  rendering of the isosurface.
> 
> if max_gradient is set to 1.001 Povray warns that max_gradient found
> is 2.038 and vice versa.

I guess POV-Ray can not in all cases find out the best max_gradient
value. You should try a very high max_gradient to be sure that this is
not the problem.

Post a reply to this message

On Tue, 10 Oct 2006 17:58:41 +0200
"Penelope20k" <pen### [at] caramailfr> wrote:

> difference{
> object { isosurface1_containedby_box }
> object {
> isosurface2_containedby_box
> translate y*-value
> }
> rotate x*90
> 
> double_illuminate
> }
> 

it makes no difference.

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Hi

marabou wrote:
> i was proud that someone can see anything in mirror with  difference.
> without you see less...

To find the problem, do the following:
- Remove all unions,differences,intersections or merges from the scene.
- Remove all objects from the scene except _one_ isosurface.
If the error is still present, there is something really wrong. In this
case I would try to tinker with the threshold and accuracy values of
the isosurface. But I'm not an expert ...
If the error is gone, you can reactivate the things one after another
and you will find out what causes the problem.

Anyway, I'm sure that this has something to do with CSG ...

Greetings
Urd

Post a reply to this message

On Tue, 10 Oct 2006 18:17:12 +0200
Urs Holzer <urs### [at] andonyarcom> wrote:

> Hi
> 
> marabou wrote:
> > i was proud that someone can see anything in mirror with  difference.
> > without you see less...
> 
> To find the problem, do the following:
> - Remove all unions,differences,intersections or merges from the scene.
> - Remove all objects from the scene except _one_ isosurface.
> If the error is still present, there is something really wrong. In this
> case I would try to tinker with the threshold and accuracy values of
> the isosurface. But I'm not an expert ...
> If the error is gone, you can reactivate the things one after another
> and you will find out what causes the problem.
> 
> Anyway, I'm sure that this has something to do with CSG ...
> 
> Greetings
> Urd

thank you for your ideas. 
I had the same but it does not help.

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"marabou" <not### [at] availableyet> wrote in message 
news:200### [at] availableyet...

   I'm no expert, but couldn't this be an 'inverse' situation?

    ~Steve~

Post a reply to this message

On Tue, 10 Oct 2006 17:28:20 +0100
"St." <dot### [at] dotcom> wrote:

[..]
>    I'm no expert, but couldn't this be an 'inverse' situation?
> 
[..]

pardon, what do you you mean?

Post a reply to this message

"marabou" <not### [at] availableyet> wrote in message 
news:200### [at] availableyet...
> On Tue, 10 Oct 2006 17:28:20 +0100
> "St." <dot### [at] dotcom> wrote:
>
> [..]
>>    I'm no expert, but couldn't this be an 'inverse' situation?
>>
> [..]
>
> pardon, what do you you mean?

   Well, basically, it will turn an object 'inside out', (not sure if it 
works with iso's). I'm just thinking/wondering what would happen if you used 
'inverse'  - would your original 'invisible' side now be visible in the 
mirror, and vice verse?

    If that's not viable, have you tried giving your object some 
thickness/depth to see if the problem is still there?

      ~Steve~

Post a reply to this message

On Tue, 10 Oct 2006 17:38:54 +0100
"St." <dot### [at] dotcom> wrote:

[..]
> 
>    Well, basically, it will turn an object 'inside out', (not sure if it 
> works with iso's). I'm just thinking/wondering what would happen if you used 
> 'inverse'  - would your original 'invisible' side now be visible in the 
> mirror, and vice verse?
> 
it does not work with isos.

>     If that's not viable, have you tried giving your object some 
> thickness/depth to see if the problem is still there?
> 
yes

[..]

Post a reply to this message

marabou wrote:

> hello,
> 
> currently I render a scene with an isosurface and a mirror showing
> that isosurface. isosurface is created like:
> difference{
> object { isosurface1_containedby_box }
> object {
> isosurface2_containedby_box
> translate y*-value
> }
> rotate x*90
> }
> the result is a nearly planar surface.
> the mirror has reflection 0.8.
> [...]

Could you give us the code (i.e. the function) of the isosurfaces? Could
you also post an image of one of those isosurfaces (without using CSG)?
Probably someone can then see the problem.
I don't know much about isosurfaces. So I make now a last guess about
what could be the problem and then I'll give up: Some functions are
bad, because they have infinite max_gradient. POV-Ray won't detect
that. But it should report high max_gradient values, so this is rather
not the case.

Good luck in solving the problem!

Post a reply to this message

On Tue, 10 Oct 2006 18:56:58 +0200
Urs Holzer <urs### [at] andonyarcom> wrote:

> marabou wrote:
> 
> > hello,
> > 
> > currently I render a scene with an isosurface and a mirror showing
> > that isosurface. isosurface is created like:
> > difference{
> > object { isosurface1_containedby_box }
> > object {
> > isosurface2_containedby_box
> > translate y*-value
> > }
> > rotate x*90
> > }
> > the result is a nearly planar surface.
> > the mirror has reflection 0.8.
> > [...]
> 
> Could you give us the code (i.e. the function) of the isosurfaces? Could
> you also post an image of one of those isosurfaces (without using CSG)?
> Probably someone can then see the problem.
> I don't know much about isosurfaces. So I make now a last guess about
> what could be the problem and then I'll give up: Some functions are
> bad, because they have infinite max_gradient. POV-Ray won't detect
> that. But it should report high max_gradient values, so this is rather
> not the case.
> 
> Good luck in solving the problem!
> 
it is only one CSG in image; please see p.b.images.

little explanation of code:
two arrays hold the clock steps and the spline points and are processed in macro
create_spline(...). 
variable createdsplinepath holds the spline and is used in a function f_myspline. this
function is used to create the iso contained_by box.
in macro draw_object(...) the iso is differenced by itself with a little translate to
get only the surface of iso.
then object is placed. the call to draw_object(...) gets references to the two arrays
i mentioned above.

parts of code follow (read from buttom to top):

#macro create_iso(isosteps, isopoints)
//====================================
create_spline(isosteps, isopoints, 0) //returns createdsplinepath
#undef f_myspline
#declare f_myspline = function {
   spline{
      createdsplinepath	// is the created spline
   }
}
#declare iso =
isosurface {
   function { y - f_myspline(x).x - f_myspline(z).z }
   accuracy 0.001
// max_gradient 4
   max_gradient 2.038
   contained_by { 
	box { -1,1 } 
   }
   pigment { rgb <255,255,255>/255 }
   finish {
      phong 0.5
      phong_size 10
   }
}
#end //macro create_iso

#macro draw_object(objsteps, objspline)
//=====================================
   create_iso(objsteps, objspline)
   difference {
      object { iso }
      object { iso scale <1.001,1,1.001> translate y*-0.02 }
   }
#end

#declare splsteps_m = array[]{}
#declare spl_m = array[]{}

object{
draw_object(splsteps_m, spl_m)
translate <0,-0.5,-2.5>
}

Post a reply to this message

"marabou" <not### [at] availableyet> wrote in message 
news:200### [at] availableyet...
> On Tue, 10 Oct 2006 17:38:54 +0100
> "St." <dot### [at] dotcom> wrote:
>
> [..]
>>
>>    Well, basically, it will turn an object 'inside out', (not sure if it
>> works with iso's). I'm just thinking/wondering what would happen if you 
>> used
>> 'inverse'  - would your original 'invisible' side now be visible in the
>> mirror, and vice verse?
>>
> it does not work with isos.

   Gah, I had a sneaky feeling it didn't.


>
>>     If that's not viable, have you tried giving your object some
>> thickness/depth to see if the problem is still there?
>>
> yes

  Hmm, then you have an interesting problem. I'll keep thinking on it.

   ~Steve~




>
> [..]

Post a reply to this message

On Tue, 10 Oct 2006 18:17:07 +0100
"St." <dot### [at] dotcom> wrote:

> 
> "marabou" <not### [at] availableyet> wrote in message 
> news:200### [at] availableyet...
> > On Tue, 10 Oct 2006 17:38:54 +0100
> > "St." <dot### [at] dotcom> wrote:
[..]
> >>     If that's not viable, have you tried giving your object some
> >> thickness/depth to see if the problem is still there?
> >>
> > yes
> 
>   Hmm, then you have an interesting problem. I'll keep thinking on it.
> 
[..]
have you read this:?
news.povray.org povray.newusers:14442

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Wasn't it marabou who wrote:
>
>parts of code follow (read from buttom to top):

As I said earlier, you need to specify a sensible max_trace count, or
use all_intersections, in any isosurface that's involved in CSG
operations (like your "difference").

The default max_trace is too low for the CSG.

-- 
Mike (why does nobody ever listen to me) Williams

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heureka!
it was not the keyword "hollow", it was "open"!
thank you for all the good tipps and ideas!

Post a reply to this message

"Mike Williams" <nos### [at] econymdemoncouk> wrote in message 
news:nKL### [at] econymdemoncouk...
> Wasn't it marabou who wrote:
>>
>>isosurface is invisible
>>
> As I said earlier, you need to specify a sensible max_trace count>
> ...
> Mike (why does nobody ever listen to me) Williams

D'you think sometimes maybe you're invisible too.

;o)
Chris B.

Post a reply to this message

Wasn't it marabou who wrote:
>heureka!
>it was not the keyword "hollow", it was "open"!
>thank you for all the good tipps and ideas!

Well "open" will reduce the number of intersections in certain
directions making it possible to get away with the default max_trace
setting sometimes, but if the problem comes back even with "open" you
can fix it with "all_intersections".

-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message

On Tue, 10 Oct 2006 21:14:12 +0100
Mike Williams <nos### [at] econymdemoncouk> wrote:

[..]
> setting sometimes, but if the problem comes back even with "open" you
> can fix it with "all_intersections".
> 
[..]

recognized. thank you

Post a reply to this message

On Tue, 10 Oct 2006 18:33:47 +0100
Mike Williams <nos### [at] econymdemoncouk> wrote:

[..]
> -- 
> Mike (why does nobody ever listen to me) Williams
sorry, it was not meant so.

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