POV-Ray : Newsgroups : povray.general : CSG with sphere sweeps Server Time
10 May 2021 20:26:57 EDT (-0400)
  CSG with sphere sweeps (Message 1 to 8 of 8)  
From: s day
Subject: CSG with sphere sweeps
Date: 21 Apr 2021 09:30:00
Message: <web.6080282a9709008e8de81c16a8f0b95@news.povray.org>
OK, it has been a long time since I have used POV for anything but have I
forgotten a rule about using sphere_sweeps with CSG operations?

Below code has exactly the same sphere_sweep but when viewed at the lower angle
I see artifacts:

#version 3.7;


camera {
  location  <0, 0.0,-5.0>
  look_at   <0, 0, 0>
  right     x*image_width/image_height
}

// create a regular point light source
light_source {
  0*x                  // light's position (translated below)
  color rgb <1,1,1>    // light's color
  translate <-20, 40, -20>
}

// Set a color of the background (sky)
background { color rgb< 1, 1, 1> }

difference {
 box { <-2, -5, -0.1> <2, 5, 0.1> }
union {
sphere_sweep {
    b_spline
    5,
    < 2.2, -1.75, 0>, 0.45,
    < 0, 0, 0>, 0.45,
    <-0.50, 1.25, 0>, 0.35,
    <0.65, 2.5, 0>, 0.025,
    < 0.45, 5.0, 0>, -0.35
    tolerance 0.1

    scale <0.5, .5, 2>   rotate<0,0,0>
   }  // end of sphere_sweep --

sphere_sweep {
    b_spline
    5,
    < 2.2, -1.75, 0>, 0.45,
    < 0, 0, 0>, 0.45,
    <-0.50, 1.25, 0>, 0.35,
    <0.65, 2.5, 0>, 0.025,
    < 0.45, 5.0, 0>, -0.35
    tolerance 0.1

    scale <0.5, .5, 2>   rotate<0,0,0>  translate<-0.55,-2.1,0>
   }  // end of sphere_sweep --
}
material {
texture {
pigment { rgb <0.01, 0.51, 0.51> }
finish { specular albedo .1 roughness 0.001 brilliance 2 diffuse  albedo 0.9
reflection { 0.05, .1 fresnel on } conserve_energy }
}
interior { ior 1.6 }
}

}


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From: William F Pokorny
Subject: Re: CSG with sphere sweeps
Date: 21 Apr 2021 09:51:31
Message: <60802de3$1@news.povray.org>
On 4/21/21 9:27 AM, s.day wrote:
> OK, it has been a long time since I have used POV for anything but have I
> forgotten a rule about using sphere_sweeps with CSG operations?
> 
> Below code has exactly the same sphere_sweep but when viewed at the lower angle
> I see artifacts:
> 

I'm not aware of any rule.

The scene renders fine with the current v3.8 master branch.

You don't have a cubic sweep, but I think you are very likely(1) hitting 
a closed(fixed) issue for a problem Yadgar reported and Christoph fixed 
back in 2017.

https://github.com/POV-Ray/povray/issues/287

(1) - I don't have a compile handy at the fix commit to 100% confirm it. 
In any case, the current v3.8 is OK.

Bill P.


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From: s day
Subject: Re: CSG with sphere sweeps
Date: 22 Apr 2021 02:25:00
Message: <web.60811645a82c9a50e8de81c16a8f0b95@news.povray.org>
William F Pokorny <ano### [at] anonymousorg> wrote:
> In any case, the current v3.8 is OK.
>

Thanks Bill, is there a pre-compiled/binary version of 3.8 or do I need to build
it from source?


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From: Bald Eagle
Subject: Re: CSG with sphere sweeps
Date: 22 Apr 2021 06:30:00
Message: <web.60814f75a82c9a501f9dae3025979125@news.povray.org>
"s.day" <s.d### [at] uelacuk> wrote:
> William F Pokorny <ano### [at] anonymousorg> wrote:
> > In any case, the current v3.8 is OK.
> >
>
> Thanks Bill, is there a pre-compiled/binary version of 3.8 or do I need to build
> it from source?

http://www.buckosoft.com/qtpovray/

or compile from source for standard use.


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From: s day
Subject: Re: CSG with sphere sweeps
Date: 22 Apr 2021 07:40:00
Message: <web.60816080a82c9a50e8de81c16a8f0b95@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "s.day" <s.d### [at] uelacuk> wrote:
> > William F Pokorny <ano### [at] anonymousorg> wrote:
> > > In any case, the current v3.8 is OK.
> > >
> >
> > Thanks Bill, is there a pre-compiled/binary version of 3.8 or do I need to build
> > it from source?
>
> http://www.buckosoft.com/qtpovray/
>
> or compile from source for standard use.

Thanks for the link, only seems to be linux based version, is there a Windows
version anywhere?


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From: William F Pokorny
Subject: Re: CSG with sphere sweeps
Date: 22 Apr 2021 08:28:17
Message: <60816be1$1@news.povray.org>
On 4/22/21 7:39 AM, s.day wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
>> "s.day" <s.d### [at] uelacuk> wrote:
>>> William F Pokorny <ano### [at] anonymousorg> wrote:
>>>> In any case, the current v3.8 is OK.
>>>>
>>>
>>> Thanks Bill, is there a pre-compiled/binary version of 3.8 or do I need to build
>>> it from source?
>>
>> http://www.buckosoft.com/qtpovray/
>>
>> or compile from source for standard use.
> 
> Thanks for the link, only seems to be linux based version, is there a Windows
> version anywhere?
> 
You can find a collection of pre-compiled versions at:

https://github.com/POV-Ray/povray/releases

marked as pre-releases. I think Development build 
v3.8.0-alpha.10064268+av691 was the last non-otherwise experimental one.

Unfortunately, there are known bugs not fixed in these windows binary 
releases. Something truer for the newer parser changes related to 
dictionaries and arrays. Others (Thomas?) likely know which binary 
releases work best for what features.

Bill P.


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From: Thomas de Groot
Subject: Re: CSG with sphere sweeps
Date: 24 Apr 2021 02:21:39
Message: <6083b8f3$1@news.povray.org>
Op 22/04/2021 om 14:28 schreef William F Pokorny:
> On 4/22/21 7:39 AM, s.day wrote:
>> "Bald Eagle" <cre### [at] netscapenet> wrote:
>>> "s.day" <s.d### [at] uelacuk> wrote:
>>>> William F Pokorny <ano### [at] anonymousorg> wrote:
>>>>> In any case, the current v3.8 is OK.
>>>>>
>>>>
>>>> Thanks Bill, is there a pre-compiled/binary version of 3.8 or do I 
>>>> need to build
>>>> it from source?
>>>
>>> http://www.buckosoft.com/qtpovray/
>>>
>>> or compile from source for standard use.
>>
>> Thanks for the link, only seems to be linux based version, is there a 
>> Windows
>> version anywhere?
>>
> You can find a collection of pre-compiled versions at:
> 
> https://github.com/POV-Ray/povray/releases
> 
> marked as pre-releases. I think Development build 
> v3.8.0-alpha.10064268+av691 was the last non-otherwise experimental one.
> 
> Unfortunately, there are known bugs not fixed in these windows binary 
> releases. Something truer for the newer parser changes related to 
> dictionaries and arrays. Others (Thomas?) likely know which binary 
> releases work best for what features.
> 

That is also the version I use. Afaik, it works fine for everything but 
I certainly have not used every feature in its most stressful option. ;-)

-- 
Thomas


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From: s day
Subject: Re: CSG with sphere sweeps
Date: 26 Apr 2021 08:50:00
Message: <web.6086b64ca82c9a50e8de81c16a8f0b95@news.povray.org>
Thanks Bill/Thomas,

Will download from there and give it a go.

Sean


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