Hi,

I'm pretty much new to povray and I'm trying to render my appartment.
Got the outside walls now and find a good viewing point aswell as lights.
There's a problem, though: front and backwall are solid colored, but when
you look at the floor, ceiling, left and right wall, everything looks
rather, ehr, coarse(?).
What could it be?
The project can be retrieved from: 
http://keetweej.vanheusden.com/~folkert/test.tgz
The file 'render' is the script I use to render things.
Any help is appreciated.


Folkert van Heusden

p.s. if possible: please CC me

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"Folkert van Heusden" <fol### [at] vanheusdencom> wrote in message
news:3f56566d@news.povray.org...
> Hi,

Hi,

I've rendered your scene, and I can't see anything that matches your description
of 'coarse'. For a work in progress, I cannot see any particular problems.
'Coarse' sounds as though you are describing co-incident surfaces, but I can see
no sign of that.

I rendered 'scene.pov' (not 'render.*') - is this the right scene? Have you
posted a link to the right file? If you are having problems describing the
problem, try posting an image to binaries.images with an arrow pointing at the
problem.

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In article <3f56566d@news.povray.org>,
 Folkert van Heusden <fol### [at] vanheusdencom> wrote:

> I'm pretty much new to povray and I'm trying to render my appartment.
> Got the outside walls now and find a good viewing point aswell as lights.
> There's a problem, though: front and backwall are solid colored, but when
> you look at the floor, ceiling, left and right wall, everything looks
> rather, ehr, coarse(?).

You could be a bit more precise...what exactly looks "coarse"? Are you 
getting jagged edges? Or a grainy appearance on flat-colored areas? Odd 
color shading?

If it's jagged edges, try using higher quality antialiasing settings. A 
grainy appearance could be caused by many things...jitter in area 
lights, antialiasing, method 1 media, crand, or just certain textures. 
Odd artifacts in what should be a smooth color blend...well, that's most 
likely just a result of the limited precision of computer displays. In 
24 bit mode, they will be invisible most of the time, in 16 bit mode 
they can be very visible and distracting.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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> I've rendered your scene, and I can't see anything that matches your
> description of 'coarse'. For a work in progress, I cannot see any
> particular problems. 'Coarse' sounds as though you are describing
> co-incident surfaces, but I can see no sign of that.

With coarse I mean that some walls look 'dithered': if you look at the wall
in the front (the red one), it is solid red. The ones at the left and right
etc. look, well, as if they're dithered. Like a black & white picture in a
newspaper.
 
> I rendered 'scene.pov' (not 'render.*') - is this the right scene?

Yes! 'render' is the shell-script (running unix here) which executes pov
with the parameters I use.

> Have
> you posted a link to the right file? If you are having problems describing
> the problem, try posting an image to binaries.images with an arrow
> pointing at the problem.

I've placed it on my website ( 
http://keetweej.vanheusden.com/~folkert/scene.png ). (I did that because the
uuencoding takes extra space making the download longer)


Folkert van Heusden

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>> I'm pretty much new to povray and I'm trying to render my appartment.
>> Got the outside walls now and find a good viewing point aswell as lights.
>> There's a problem, though: front and backwall are solid colored, but when
>> you look at the floor, ceiling, left and right wall, everything looks
>> rather, ehr, coarse(?).
> You could be a bit more precise...what exactly looks "coarse"? Are you
> getting jagged edges? Or a grainy appearance on flat-colored areas? Odd
> color shading?

Yes, a grainy appearance! That's what I mean, *I think* :-) (not a native
english speaker as you've probably guessed by now).
I've put an example online at:
http://keetweej.vanheusden.com/~folkert/scene.png

> If it's jagged edges, try using higher quality antialiasing settings. A
> grainy appearance could be caused by many things...jitter in area
> lights, antialiasing, method 1 media, crand, or just certain textures.
> Odd artifacts in what should be a smooth color blend...well, that's most
> likely just a result of the limited precision of computer displays. In
> 24 bit mode, they will be invisible most of the time, in 16 bit mode
> they can be very visible and distracting.

Yes, but its not like "if you look closely you see some weird pixels", it's
more like the whole picture is strange.


Folkert van Heusden

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On Thu, 04 Sep 2003 21:14:43 +0200, Folkert van Heusden <fol### [at] vanheusdencom>
wrote:

>
>I've put an example online at:
>http://keetweej.vanheusden.com/~folkert/scene.png
>
Well I rendered your files on my XP m/c and they are ok not like above. If that
is any comfort. I almost recognise the problem and I am sure if one of the
texture experts looks at them they will spot it, Sorry.
Regards
        Stephen

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"Stephen McAvoy" <McA### [at] aolcom> wrote in message
news:dggflvsliimbvn4lias2e1d7887vgv0hvt@4ax.com...
> On Thu, 04 Sep 2003 21:14:43 +0200, Folkert van Heusden
<fol### [at] vanheusdencom>
> wrote:
> >
> >I've put an example online at:
> >http://keetweej.vanheusden.com/~folkert/scene.png
> >
> Well I rendered your files on my XP m/c and they are ok not like above. If
that
> is any comfort. I almost recognise the problem and I am sure if one of the
> texture experts looks at them they will spot it, Sorry.

Looks like it could be light_source(s) at exact position of surface(s).
Could be simple precision errors. I noticed this was being done via a
command line form of POV so that might be bug-fixed since its release. Just
a guess.

Although, I also rendered it now and found no similar appearance, no
speckling. My first thought when seeing the image was 'crand' in a finish
statement, and yet this is obviously not the case. That leaves coincident
surfaces or lights. That doesn't seem to be happening, if I'm reading the
numbers right. The fact it renders okay for me too leaves me without an easy
way to adjust wall or light positions to see what would fix the problem. I'm
wondering if that light_source at one million units could be trouble for an
earlier version of POV.

P.S. to Stephen McAvoy: I suspect I've deleted emails of yours from my AOL
mailbox during mass deletions of junk mail. I seldom use AOL except to chat
or check on special interest things there. I put two and two together when I
saw your email address here and recall a similar (same?) name in the AOL
mail. Sincere apologies if so. Just now checked InverseZ mail and had three
POV-related ones there out of 38. I really mass delete there without hardly
looking.

Bob H.

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Hi Folkert,

as many others, I can't see the grain in the picture I've rendered with
your code. What you've got is the result of coincident surfaces -- are
you using an older, less robust version of POV-Ray?

The source of most of the graininess are boxes with zero thickness:
POV-Ray can't (couldn't?) decide which of the coincident surfaces is
hit first by a camera ray. For example the "vloer" box is a
box { <0, 0, 0>, <-971.5, 0, 989> ... }, i.e. has no y-thickness.

Another cause of graininess are differences where the cut object and
the cutting object share (part of) a surface, for example the "muur vor"
and the "deur" both have a lower y=0. Their upper y is O.K., so you
seem to have read "3.3.6.1. Co-incident Surfaces", but have not applied
this everywhere where neccessary. (BTW the red wall is better modelled
as two differences (box to the left to the door minus two windows and box
to the right of the door minus window): this will be slightly faster
because the objects are smaller and the number of 'subtracted' objects
is smaller.)

The surfaces of the window-holes are black because neither the boxes used
for cutting them nor the whole difference have a texture, so they get the
default texture which is black. Probably you want
    difference {
      box { /*wall box*/ ... }
      box { /*window hole*/ ... texture { /*window hole texture*/ } }
      texture { /*wall texture*/ }
      }
or
    difference {
      box { /*wall box*/ ... }
      box { /*window hole*/ ... }
      texture { /*texture for whole wall*/ }
      }
Or read "6.7.10 Cutaway Textures".

I don't understand why you used so many light_sources, some of them even
below the floor. Because they all are 100% white, almost all colors are
saturated, even in partially shadowed areas. I suggest to replace all
"White" in zon.pov by "White*Bright" and put
   #declare Bright=.2;
at the beginning of zon.pov. Then render this and also try other values
for Bright.

The include files should have an .inc extension (not .pov). This is not
neccessary for POV-Ray, but helpful for us humans ...

My last suggestion (for now ... :D) is to use variables with informative
names instead of constants -- this makes the code much more readable for
you and those who want to help and makes many changes much easier. Assume you want to
see what your appartement would look like if
the ceiling were
a bit higher: much work with your code, but simple with code like this:
    #declare WallFinish = finish { diffuse 1 }
    #declare Epsilon     = 0.1; // used as offset to avoid coincidences
    #declare WallThick   = 25.5;
    #declare CeilInside  = 260; // change only this to make a higher room
    #declare CeilOutside = CeilInside+WallThick;
    #declare LeftInside  = -971.5;
    #declare LeftOutside = LeftInside-WallThick;
    #declare RightInside = 0;
    // etc. ...
    // muur achter
    difference {
      // buitenmuur
      box {
        <RightInside, FloorInside, BackInside >,
        <LeftInside , CeilInside , BackOutside>
        // this is most easily read (and written) by columns:
        // x goes from LeftInside to RightInside
        // y goes from FloorInside to CeilInside
        // z goes from BackInside to BackOutside
        }
      // grote raam
      box {
        < -28.5, WindowBottom      , BackInside -Epsilon>,
        <-330.5, CeilInside+Epsilon, BackOutside+Epsilon>
        texture { WindowBorderTex }
        }
      texture {
        pigment { color Yellow }
        finish { WallFinish }
        }
      }


Sputnik

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"Folkert van Heusden" <fol### [at] vanheusdencom> wrote in message
news:3f56566d@news.povray.org...

   It looks just like a 'normal' statement has been used on the walls,
is this correct?

   ~Steve~

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On Wed, 03 Sep 2003 23:00:28 +0200, Folkert van Heusden
<fol### [at] vanheusdencom> wrote:

>What could it be?

It may sound like a very stupid question, but are you sure you're not
displaying (not rendering, that's in TrueColor) in 256 or 65536
colors?


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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