POV-Ray : Newsgroups : povray.off-topic : Heightfield modification Server Time
8 Jul 2024 08:34:06 EDT (-0400)
  Heightfield modification (Message 12 to 21 of 21)  
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From: Stephen
Subject: Re: Heightfield modification
Date: 18 Aug 2015 12:48:47
Message: <55d361ef$1@news.povray.org>
On 8/18/2015 5:22 PM, Mike Horvath wrote:
> On 8/15/2015 6:43 AM, Stephen wrote:
>> On 8/15/2015 10:05 AM, Le_Forgeron wrote:
>>> Assuming the height-field is created from an image, what you seems to
>>> want is a local filter to detect slope and make them flat... aka
>>> uniform in colour.
>>>
>>> With the exception of nearest 24 vertical unit rounding, that looks
>>> like a color/palette reduction in any decent picture manipulation
>>> program. That kind of thing.
>>
>> I was wondering if the slop pattern could be used to create a modified
>> image to use as a height field.
>>
>
> Can POVray produce images suitable for using as heightfields?

Yes, use an orthographic camera and a square aspect ratio.

But I don't have enough experience to guide you on the slope pattern.

-- 

Regards
     Stephen


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From: Mike Horvath
Subject: Re: Heightfield modification
Date: 19 Aug 2015 20:17:17
Message: <55d51c8d$1@news.povray.org>
On 8/18/2015 12:48 PM, Stephen wrote:
> On 8/18/2015 5:22 PM, Mike Horvath wrote:
>> Can POVray produce images suitable for using as heightfields?
>
> Yes, use an orthographic camera and a square aspect ratio.
>
> But I don't have enough experience to guide you on the slope pattern.
>

What I mean is, isn't there a special 16 bit format used by 
heightfields? Can POVray save as this special format?


Mike


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From: Nekar Xenos
Subject: Re: Heightfield modification
Date: 19 Aug 2015 22:18:09
Message: <op.x3m90ebkufxv4h@xena>
On Thu, 20 Aug 2015 02:17:24 +0200, Mike Horvath <mik### [at] gmailcom>  
wrote:

> On 8/18/2015 12:48 PM, Stephen wrote:
>> On 8/18/2015 5:22 PM, Mike Horvath wrote:
>>> Can POVray produce images suitable for using as heightfields?
>>
>> Yes, use an orthographic camera and a square aspect ratio.
>>
>> But I don't have enough experience to guide you on the slope pattern.
>>
>
> What I mean is, isn't there a special 16 bit format used by  
> heightfields? Can POVray save as this special format?
>

Yes there is. But I can't remember the command line settings. I think it's  
in the docs.

-- 
-Nekar Xenos-


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From: clipka
Subject: Re: Heightfield modification
Date: 20 Aug 2015 01:04:02
Message: <55d55fc2$1@news.povray.org>
Am 20.08.2015 um 02:17 schrieb Mike Horvath:
> On 8/18/2015 12:48 PM, Stephen wrote:
>> On 8/18/2015 5:22 PM, Mike Horvath wrote:
>>> Can POVray produce images suitable for using as heightfields?
>>
>> Yes, use an orthographic camera and a square aspect ratio.
>>
>> But I don't have enough experience to guide you on the slope pattern.
>>
> 
> What I mean is, isn't there a special 16 bit format used by
> heightfields? Can POVray save as this special format?

There /used/ to be a special variant of the .gif format known as POT
files, back in the good old times when most file formats were limited to
8 bit (total!) per pixel.

To my knowledge, POV-Ray was never able to write this format itself (in
fact it seems that the only commonly known program that ever wrote this
type of format was the infamous FractInt), and I'm not even sure whether
POV-Ray can still read it.

Also IIRC there's some hackish solution in the code for using two colour
channels of a 3*8 bits-per-pixel file format to achieve a depth of 16
bits; again, I'm not sure whether POV-Ray can also write this format.

Be that as it may, all those solutions are pretty much obsolete these
days; POV-Ray can use any of the supported image file formats for height
field data input, including several contemporary ones that natively
support a depth of 16 bits per colour channel (such as PNG).

To generate an output file with 16 bits per colour channel, use the
"Bits_Per_Color=n" ini file option, or the "+Fxn" command-line option
where "x" is the letter representing the desired file type, such as "N"
for PNG.

Specifically for the use with height fields, POV-Ray also supports
greyscale-only 16-bit file output (which saves a bit of disk space and
is faster and more memory-efficient when used as input) for the PNG file
format; to enable this, use "Greyscale_Output=true" or "+FNg".


One thing worth noting is that you should specify the "File_Gamma=1" ini
file option and "assumed_gamma 1.0" global scene setting when generating
files for height fields.


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From: Stephen
Subject: Re: Heightfield modification
Date: 20 Aug 2015 02:20:42
Message: <55d571ba$1@news.povray.org>
On 8/20/2015 6:03 AM, clipka wrote:
> There/used/  to be a special variant of the .gif format known as POT
> files, back in the good old times when most file formats were limited to
> 8 bit (total!) per pixel.
>
> To my knowledge, POV-Ray was never able to write this format itself (in
> fact it seems that the only commonly known program that ever wrote this
> type of format was the infamous FractInt), and I'm not even sure whether
> POV-Ray can still read it.

That is how I first heard of PovRay. From the FractInt (why infamous?) 
help doc.

-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Heightfield modification
Date: 20 Aug 2015 03:41:45
Message: <55d584b9$1@news.povray.org>
On 20-8-2015 8:20, Stephen wrote:
> On 8/20/2015 6:03 AM, clipka wrote:
>> There/used/  to be a special variant of the .gif format known as POT
>> files, back in the good old times when most file formats were limited to
>> 8 bit (total!) per pixel.
>>
>> To my knowledge, POV-Ray was never able to write this format itself (in
>> fact it seems that the only commonly known program that ever wrote this
>> type of format was the infamous FractInt), and I'm not even sure whether
>> POV-Ray can still read it.
>
> That is how I first heard of PovRay. From the FractInt (why infamous?)
> help doc.
>

Yes, POV-Ray can use POT files for height_fields. See the Docs.

Fractint was far from infamous. To the contrary, it was the most 
formidable mandelbrot generator of its days available to the general 
public. It contributed to my discovery and use of POV-Ray too.

-- 
Thomas


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From: clipka
Subject: Re: Heightfield modification
Date: 20 Aug 2015 07:20:59
Message: <55d5b81b$1@news.povray.org>
Am 20.08.2015 um 08:20 schrieb Stephen:
> On 8/20/2015 6:03 AM, clipka wrote:
>> There/used/  to be a special variant of the .gif format known as POT
>> files, back in the good old times when most file formats were limited to
>> 8 bit (total!) per pixel.
>>
>> To my knowledge, POV-Ray was never able to write this format itself (in
>> fact it seems that the only commonly known program that ever wrote this
>> type of format was the infamous FractInt), and I'm not even sure whether
>> POV-Ray can still read it.
> 
> That is how I first heard of PovRay. From the FractInt (why infamous?)
> help doc.

Infamous because, while I hate to admit it, my English isn't perfect :-}

For some reason I was convinced that the word could be used with a
connotation of respect for outstanding achievements and bravado
bordering (or beyond) the illegal - possibly because the German
equivalent, "berüchtigt", can sometimes be used in this sense
(especially in the combination "berühmt-berüchtigt").

Strike that, and insert "badass" instead.


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From: Stephen
Subject: Re: Heightfield modification
Date: 20 Aug 2015 08:36:01
Message: <55d5c9b1$1@news.povray.org>
On 8/20/2015 12:20 PM, clipka wrote:
> Infamous because, while I hate to admit it, my English isn't perfect :-}
>

It is probably better than mine. :-)
Init!

> For some reason I was convinced that the word could be used with a
> connotation of respect for outstanding achievements and bravado
> bordering (or beyond) the illegal - possibly because the German
> equivalent, "berüchtigt", can sometimes be used in this sense
> (especially in the combination "berühmt-berüchtigt").
>

Google translates berüchtigt as notorious. Which fits in with your 
definition. I would have said the renowned Fractint.


> Strike that, and insert "badass" instead.
>

I don't suppose it is any easier when words like wicked and cool, have 
reversed their meanings in recent years.

-- 

Regards
     Stephen


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From: Mike Horvath
Subject: Re: Heightfield modification
Date: 20 Aug 2015 20:31:40
Message: <55d6716c$1@news.povray.org>
On 8/16/2015 12:21 PM, Mike Horvath wrote:
> How do I calculate the slope of a 3D triangle with respect to the ground
> plane? And I need a non-POVray solution. Thanks.
>
> Mike


Wow, Stack Exchange is stumped too! So far about a half dozen people 
haven't been able to figure it out.


Mike


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From: Thomas de Groot
Subject: Re: Heightfield modification
Date: 21 Aug 2015 03:18:49
Message: <55d6d0d9$1@news.povray.org>
On 20-8-2015 13:20, clipka wrote:
> For some reason I was convinced that the word could be used with a
> connotation of respect for outstanding achievements and bravado
> bordering (or beyond) the illegal - possibly because the German
> equivalent, "berüchtigt", can sometimes be used in this sense
> (especially in the combination "berühmt-berüchtigt").

That is interesting. I think that in Dutch (beroemd-berucht) that would 
not be possible. At least I think so... Language is a tricky business.

-- 
Thomas


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