In article <40b0d0ad@news.povray.org>,
 "Eric DeGiuli" <eri### [at] NOSPAMutorontoca> wrote:

> I've just started using POV ray for some scientific visualization but I'm
> having problems with density files.  I'm using the patch to allow 16 bit
> floats as data (
> http://staff.aist.go.jp/r-suzuki/e/povray/iso/df_body.htm ) - I wish there
> was a 3.6 beta available so that I could avoid using the patch!  My data is
> a 200x200x32 volume of cloud data, scaled to be between 0 and 0.99.  I'm
> using the data in a media block, with nothing fancy.  It looks like my data
> is being clipped either on import or during rendering, because it should be
> really smooth. (see image)

Well, remember that you're viewing it at 8 bits per component. That's 
256 levels, from 0 to 255. Try rendering to 48 bit PNG and viewing it in 
a program that does dithering. And I couldn't get accurate colors from 
your JPEG, so I'm not really sure what you're seeing. Also, make sure 
you're writing the data in the correct byte order, etc.

Aside from that, this group is for non-binary posts only. If you want to 
post an image, please post it in povray.binaries.images.

-- 
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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Here is a version where I've increased the contrast in post:

http://individual.utoronto.ca/edegiuli/mediaproblem2.jpg

There should be smooth transitions everywhere, but you can see there are
places where the colour changes very sharply.  Moreover, you can see that
there are places where a dark part is inside a lighter spot, which indicates
the the interior region has been clipped and set back to dark colour.  In
1D:

http://individual.utoronto.ca/edegiuli/clipping.jpg

Like I said, my data is scaled between 0 and 0.99, so it looks like it is
being clipped as the density is integrated over a ray through the media.

Eric

"Christopher James Huff" <cja### [at] earthlinknet> wrote in message
news:cjameshuff-3C0372.12093123052004@news.povray.org...
> In article <40b0d0ad@news.povray.org>,
>  "Eric DeGiuli" <eri### [at] NOSPAMutorontoca> wrote:
>
> > I've just started using POV ray for some scientific visualization but
I'm
> > having problems with density files.  I'm using the patch to allow 16 bit
> > floats as data (
> > http://staff.aist.go.jp/r-suzuki/e/povray/iso/df_body.htm ) - I wish
there
> > was a 3.6 beta available so that I could avoid using the patch!  My data
is
> > a 200x200x32 volume of cloud data, scaled to be between 0 and 0.99.  I'm
> > using the data in a media block, with nothing fancy.  It looks like my
data
> > is being clipped either on import or during rendering, because it should
be
> > really smooth. (see image)
>
> Well, remember that you're viewing it at 8 bits per component. That's
> 256 levels, from 0 to 255. Try rendering to 48 bit PNG and viewing it in
> a program that does dithering. And I couldn't get accurate colors from
> your JPEG, so I'm not really sure what you're seeing. Also, make sure
> you're writing the data in the correct byte order, etc.
>
> Aside from that, this group is for non-binary posts only. If you want to
> post an image, please post it in povray.binaries.images.
>
> -- 
> 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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