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From: kurtz le pirate
Subject: How to ...
Date: 22 Nov 2021 11:23:08
Message: <619bc3ec$1@news.povray.org>
Hello,

I have a surface defined by a set of points <x,y,z> and for each point, 
its color.

In your opinion, which object/method is the most appropriate to 
represent such a surface?




-- 
Kurtz le pirate
Compagnie de la Banquise


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From: Bald Eagle
Subject: Re: How to ...
Date: 22 Nov 2021 13:40:00
Message: <web.619be376d5fe89401f9dae3025979125@news.povray.org>
kurtz le pirate <kur### [at] gmailcom> wrote:
> Hello,
>
> I have a surface defined by a set of points <x,y,z> and for each point,
> its color.
>
> In your opinion, which object/method is the most appropriate to
> represent such a surface?

I'm thinking that the most straightforward thing would be to use
smooth_triangles.

Alternately, maybe you could set up a network of bezier patches, and use your
color information to render a separate scene of boxes that would give you an
image to use as an image_map for uv_mapping your bezier patch union {}.

Might be able to do something with splines and functions ....

It all may depend on how many points you have.


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From: Francois LE COAT
Subject: Re: How to ...
Date: 23 Nov 2021 11:30:12
Message: <619d1714$1@news.povray.org>
Hi,

Bald Eagle writes:
> kurtz le pirate wrote:
>> I have a surface defined by a set of points <x,y,z> and for each point
,
>> its color.
>>
>> In your opinion, which object/method is the most appropriate to
>> represent such a surface?
> 
> I'm thinking that the most straightforward thing would be to use
> smooth_triangles.
> 
> Alternately, maybe you could set up a network of bezier patches, and us
e your
> color information to render a separate scene of boxes that would give y
ou an
> image to use as an image_map for uv_mapping your bezier patch union {}.

> 
> Might be able to do something with splines and functions ....
> 
> It all may depend on how many points you have.

For example, *.TRI format of 3D shapes contain <x,y,z> coordinates, and
a color affected to these. If you use TRI2POV it gives a surface like...

	<https://www.youtube.com/watch?v=Yf7q2KdAS-4>

When you use TRI2POV it converts the surface in a set of smooth_triangle
that can render the surface with ray-tracing. That exists since the very
first versions of POV-Ray, and produces a very nice result.

I hope that it is what you're thinking about. Some 3D file formats, like
*.TRI is perfect to describe that kind of colored 3D surfaces. It's easy

Regards,

-- 

Author of Eureka 2.12 (2D Graph Describer, 3D Modeller)
<http://eureka.atari.org/>


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From: Bald Eagle
Subject: Re: How to ...
Date: 23 Nov 2021 13:40:00
Message: <web.619d3540d5fe89401f9dae3025979125@news.povray.org>
Francois LE COAT <lec### [at] atariorg> wrote:

> For example, *.TRI format of 3D shapes contain <x,y,z> coordinates, and
> a color affected to these. If you use TRI2POV it gives a surface like...
>
>  <https://www.youtube.com/watch?v=Yf7q2KdAS-4>
>
> When you use TRI2POV it converts the surface in a set of smooth_triangle
> that can render the surface with ray-tracing. That exists since the very
> first versions of POV-Ray, and produces a very nice result.
>
> I hope that it is what you're thinking about. Some 3D file formats, like
> *.TRI is perfect to describe that kind of colored 3D surfaces. It's easy

I don't believe I am aware of TRI2POV.  Where is it available?
I'm sure I have asked a similar question in the past, so I'm thinking that there
are a lot of other people who are unaware of this utility.


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From: Francois LE COAT
Subject: Re: How to ...
Date: 23 Nov 2021 15:00:04
Message: <619d4844$1@news.povray.org>
Hi,

Bald Eagle writes:
> Francois LE COAT wrote:
>> For example, *.TRI format of 3D shapes contain <x,y,z> coordinates, an
d
>> a color affected to these. If you use TRI2POV it gives a surface like.
..
>>
>>   <https://www.youtube.com/watch?v=Yf7q2KdAS-4>
>>
>> When you use TRI2POV it converts the surface in a set of smooth_triang
le
>> that can render the surface with ray-tracing. That exists since the ve
ry
>> first versions of POV-Ray, and produces a very nice result.
>>
>> I hope that it is what you're thinking about. Some 3D file formats, li
ke
>> *.TRI is perfect to describe that kind of colored 3D surfaces. It's ea
sy
> 
> I don't believe I am aware of TRI2POV.  Where is it available?
> I'm sure I have asked a similar question in the past, so I'm thinking t
hat there
> are a lot of other people who are unaware of this utility.

I have C sources for TRI2POV. But I remembered that it's ATARI software:
"
TRI-POV Converter Version 1.0 Sept/97
Copyright (c) 1993 by Steve Anger
And 97 by Archimedium

This program converts .TRI files generated by the Atari programs
to POV-Ray or Vivid raytracer scene files. Bounding shapes are
automatically generated for POV-Ray to greatly reduce the rendering time.



Syntax:  tri2pov inputfile[.tri] [outputfile] [options]

Options:
-snnn    - Generates smooth triangles. The boundaries between triangles
            are only smoothed if the angle between the triangles is less
            that nnn degrees. -s0 will not smooth any triangles while
            -s180 will smooth all triangles. Values from -s45 to -s90
            usually work well. If unspecified smoothing defaults to -s60.


-op      - Output to POV-Ray 1.0 format
-op2     - Output to POV-Ray 2.0 format (2.0 is unreleased as yet)
-op3     - Output to POV-Ray 3.0 format (default)
-ov      - Output to Vivid 2.0 format
-or      - Output to Raw triangle format.

-lxnnn   - Set look_at x coord to nnn
-lynnn   -  '     '    y   '   '   '
-lznnn   -  '     '    z   '   '   '

-vxnnn   - Set view_point x coord to nnn
-vynnn   -  '       '     y   '   '   '
-vznnn   -  '       '     z   '   '   '

e.g. tri2pov car.tri car.pov -s60.0


                                   Steve Anger, Guelph, ON, Canada
                                   CIS: 70714,3113
                                   Internet: 707### [at] compuservecom
                                   ADEnet Boards i.e.:TGA: (510)524-2780

Archimedium WEB: http://www.ief.u-psud.fr/~lecoat
E-mail: lec### [at] iefu-psudfr
"
I modified it a long time ago. It works well. I can send you sources...

Best regards,

-- 

Author of Eureka 2.12 (2D Graph Describer, 3D Modeller)
http://eureka.atari.org/


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From: Bald Eagle
Subject: Re: How to ...
Date: 23 Nov 2021 19:30:00
Message: <web.619d872fd5fe89401f9dae3025979125@news.povray.org>
Francois LE COAT <lec### [at] atariorg> wrote:

> I have C sources for TRI2POV. But I remembered that it's ATARI software:

:O
Maybe you can post a zip to the utilities group - then several people can look
it over and play with it.

The C and C++ programmers, the povray macro writers, etc...

It sounds like a great utility to make generally available!


Thanks   :)


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From: Francois LE COAT
Subject: Re: How to ...
Date: 24 Nov 2021 04:30:10
Message: <619e0622$1@news.povray.org>
Hi,

Bald Eagle writes:
> Francois LE COAT wrote:
>> I have C sources for TRI2POV. But I remembered that it's ATARI softwar
e:
> 
> :O
> Maybe you can post a zip to the utilities group - then several people c
an look
> it over and play with it.
> 
> The C and C++ programmers, the povray macro writers, etc...
> 
> It sounds like a great utility to make generally available!
> 
> 
> Thanks   :)

The author of TRI2POV is Steve Anger, who is a member of the POV-Team:

<https://www.povray.org/documentation/view/3.6.0/204/>

I can't publish the C sources, because it is copyrighted. I can send
you something, privately. But if it should be opened publicly, we
should ask Steve Anger, about opening his code from 1993...

What do you think of that?

Best regards,

-- 

Author of Eureka 2.12 (2D Graph Describer, 3D Modeller)
http://eureka.atari.org/


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From: Alain Martel
Subject: Re: How to ...
Date: 24 Nov 2021 11:49:18
Message: <619e6d0e$1@news.povray.org>
Le 2021-11-23 à 15:00, Francois LE COAT a écrit :

> This program converts .TRI files generated by the Atari programs
> to POV-Ray or Vivid raytracer scene files. Bounding shapes are
> automatically generated for POV-Ray to greatly reduce the rendering time.
> 
> 
That part about adding bounding is no longer useful. It was useful to 
manually bound things back then, but, the automatic bounding have 
improved dramatically since 1993.
Now, not using those bounding often result in better performances.

Remember that adding bounded_by to an union suppress the normal bounding 
of it's components. That mean that any ray that enters that bounding box 
have to get tested against every individual primitives contained in that 
union.


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From: Bald Eagle
Subject: Re: How to ...
Date: 24 Nov 2021 16:10:00
Message: <web.619ea93fd5fe89401f9dae3025979125@news.povray.org>
Francois LE COAT <lec### [at] atariorg> wrote:
> Thanks   :)
>
> The author of TRI2POV is Steve Anger, who is a member of the POV-Team:
>
> <https://www.povray.org/documentation/view/3.6.0/204/>
>
> I can't publish the C sources, because it is copyrighted. I can send
> you something, privately. But if it should be opened publicly, we
> should ask Steve Anger, about opening his code from 1993...
>
> What do you think of that?
>
> Best regards,

Sure - one would hope that he would be fine with that.
Feel free to send me an email as well.

- Bill


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From: kurtz le pirate
Subject: Re: How to ...
Date: 26 Nov 2021 09:39:25
Message: <61a0f19d$1@news.povray.org>
On 23/11/2021 21:00, Francois LE COAT wrote:
> Hi,
> 
> Bald Eagle writes:
>> Francois LE COAT wrote:
>>> For example, *.TRI format of 3D shapes contain <x,y,z> coordinates, and
>>> a color affected to these. If you use TRI2POV it gives a surface like...
>>>

>>>
>>> When you use TRI2POV it converts the surface in a set of smooth_triangle
>>> that can render the surface with ray-tracing. That exists since the very
>>> first versions of POV-Ray, and produces a very nice result.
>>>
>>> I hope that it is what you're thinking about. Some 3D file formats, like
>>> *.TRI is perfect to describe that kind of colored 3D surfaces. It's easy
>>

>> I'm sure I have asked a similar question in the past, so I'm thinking 
>> that there
>> are a lot of other people who are unaware of this utility.
> 
> I have C sources for TRI2POV. But I remembered that it's ATARI software:
> "
> TRI-POV Converter Version 1.0 Sept/97
> Copyright (c) 1993 by Steve Anger
> And 97 by Archimedium
> 
> This program converts .TRI files generated by the Atari programs
> to POV-Ray or Vivid raytracer scene files. Bounding shapes are
> automatically generated for POV-Ray to greatly reduce the rendering time.
> 
> 

> 
> Options:





> 





> 



> 



> 
> e.g. tri2pov car.tri car.pov -s60.0
> 
> 




> 
> Archimedium WEB: http://www.ief.u-psud.fr/~lecoat
> E-mail: lec### [at] iefu-psudfr
> "
> I modified it a long time ago. It works well. I can send you sources...
> 
> Best regards,
> 

This utility looks interesting.
I'd like the sources. If it is not too complicated, the conversion from 
C to POV SDL can be considered.

My email address is valid.


-- 
Kurtz le pirate
Compagnie de la Banquise


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