El 01/04/16 a las 22:46, LanuHum escribió:
> Very good! :)

   Thanks!

> Now show the coast.

   If I do, don't expect to see any breaking wave there... As Thomas
said, it must be feasible, but just acquiring the knowledge to do this
procedurally will consume the rest of my lifetime.

> From the camera.

   I don't know any other way to trace a scene except from the camera. ;)

> Such foreshortening

   ??? ..I guess the translator got confused here.


--
jaime

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El 02/04/16 a las 08:50, Thomas de Groot escribió:
> That is something I have unsuccessfully tried to do with
> isosurfaces. Should be possible but...
>

  Yes, it should be possible, but the complexity behind the phenomenon is
mind-blowing.

--
jaime

Post a reply to this message

Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> El 01/04/16 a las 22:46, LanuHum escribi�:
> > Very good! :)
>
>    Thanks!
>
> > Now show the coast.
>
>    If I do, don't expect to see any breaking wave there... As Thomas
> said, it must be feasible, but just acquiring the knowledge to do this
> procedurally will consume the rest of my lifetime.
>


I speak about simulation in graphics editors.
You speak about programming and mathematician.



> > From the camera.
>
>    I don't know any other way to trace a scene except from the camera. ;)
>
> > Such foreshortening
>
>    ??? ..I guess the translator got confused here.
>
>
> --
> jaime

Sorry!
The camera is located ashore.
I wanted to see this coast.
That it was clear, I attached the picture, but you already don't understand.
My picture: where camera?
The look captures the coast on which there is a camera.
But, the essence is clear already. You way: Programming and mathematician.

NOT RMB, LMB, Middle and scroll, only keyboard.  :):):)

I said earlier that Povray can't bend a surface, using normal as it does the
Blender.
You well repeated that ocean which I showed. But, it is very difficult method
for users the Blender. :)))))

Post a reply to this message

El 02/04/16 a las 10:31, LanuHum escribió:
> I speak about simulation in graphics editors.

   Then that has nothing to do with POV-Ray... from that point of view,
it doesn't matter what POV-Ray can do, you just export the final mesh
and render it with a suitable material/media.

> The camera is located ashore. I wanted to see this coast. That it was
> clear, I attached the picture, but you already don't understand.

   I did understand, but wondered what you wrote in russian that got
translated as "foreshortening".

> You well repeated that ocean which I showed. But, it is very
> difficult method for users the Blender. :)))))

   As I said above, your exporter users should be making the ocean
surface by blender means (i.e.:
https://www.blender.org/manual/modeling/modifiers/simulate/ocean.html).
In my opinion, your job should only consist on providing good materials
on the POV-Ray export.

   Anyhow, if you wanted to let your users to use POV-Ray as a modeler in
this case, you could always use the HF_Square() macro to export the
height_field function as a mesh, but I wonder how would you allow them
preview that in Blender.

--
jaime

Post a reply to this message

On 4/2/2016 3:17 AM, Nekar Xenos wrote:
> On 2016/04/01 07:36 PM, Stephen wrote:

>>
>>
>>>> That I believe. I spent weeks trying to get a good result using Tek's
>>>> isosurface, not very well. :(
>>>>
>>>> http://www.tc-rtc.co.uk/portfolio/Stephen/366/index.html
>>>>
>>>
>>>    Nice idea, but yes, the foam got a bit messy... ;)
>>>
>>
>> And that was the best of the pick. :-(
>>
>>
> I think this actually looks really good. I like the style.

Thank you. You are one of the few. :-)

> But not for
> realism though.
>

I am not known for my realism. ;-)

-- 

Regards
     Stephen

Post a reply to this message

Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> El 02/04/16 a las 10:31, LanuHum escribi�:
> > I speak about simulation in graphics editors.
>
>    Then that has nothing to do with POV-Ray... from that point of view,
> it doesn't matter what POV-Ray can do, you just export the final mesh
> and render it with a suitable material/media.
>

Some render have the option "displace"
Look:
http://news.povray.org/povray.binaries.images/message/%3Cweb.56ff96e9c8daa117a3e03fe0%40news.povray.org%3E/#%3Cweb.56ff
96e9c8daa117a3e03fe0%40news.povray.org%3E

> > The camera is located ashore. I wanted to see this coast. That it was
> > clear, I attached the picture, but you already don't understand.
>
>    I did understand, but wondered what you wrote in russian that got
> translated as "foreshortening".
>

The online translator puts equality sign "foreshortening" = "perspective"
:)))))


> > You well repeated that ocean which I showed. But, it is very
> > difficult method for users the Blender. :)))))
>
>    As I said above, your exporter users should be making the ocean
> surface by blender means (i.e.:
> https://www.blender.org/manual/modeling/modifiers/simulate/ocean.html).
> In my opinion, your job should only consist on providing good materials
> on the POV-Ray export.
>


Yes.


>    Anyhow, if you wanted to let your users to use POV-Ray as a modeler in
> this case, you could always use the HF_Square() macro to export the
> height_field function as a mesh, but I wonder how would you allow them
> preview that in Blender.
>

If macro creates the file (with mesh2), then I can load it in a scene.

> --
> jaime

Post a reply to this message

Stephen <mca### [at] aolcom> wrote:
> On 4/2/2016 3:17 AM, Nekar Xenos wrote:

> > But not for
> > realism though.
> >
>
> I am not known for my realism. ;-)
>
> --
>
> Regards
>      Stephen

I am not interested in realism. But, I want that the viewer understood that I
drew.
:))))

Post a reply to this message

On 4/2/2016 12:01 PM, LanuHum wrote:
> Stephen <mca### [at] aolcom> wrote:
>> On 4/2/2016 3:17 AM, Nekar Xenos wrote:
>
>>> But not for
>>> realism though.
>>>
>>
>> I am not known for my realism. ;-)
>>
>> --
>>
>> Regards
>>       Stephen
>
> I am not interested in realism. But, I want that the viewer understood that I
> drew.
> :))))
>

That is the best that I can hope for.
I know my place. ;)

(A tribute to the late Ronnie Corbett.)

-- 

Regards
     Stephen

Post a reply to this message

Stephen <mca### [at] aolcom> wrote:
> On 4/2/2016 12:01 PM, LanuHum wrote:
> > Stephen <mca### [at] aolcom> wrote:
> >> On 4/2/2016 3:17 AM, Nekar Xenos wrote:
> >
> >>> But not for
> >>> realism though.
> >>>
> >>
> >> I am not known for my realism. ;-)
> >>
> >> --
> >>
> >> Regards
> >>       Stephen
> >
> > I am not interested in realism. But, I want that the viewer understood that I
> > drew.
> > :))))
> >
>
> That is the best that I can hope for.
> I know my place. ;)
>
> (A tribute to the late Ronnie Corbett.)
>
> --
>
> Regards
>      Stephen


Long ago in shop I photographed a pattern? (pictures,images?) reproduction.
I don't see it realistic, but, I would like to simulate it for animation.
For me it is very beautiful!

Post a reply to this message

Attachments:
Download 'sea_pic.jpg' (176 KB)

Preview of image 'sea_pic.jpg'

On 4/2/2016 2:56 PM, LanuHum wrote:
>
> Long ago in shop I photographed a pattern? (pictures,images?) reproduction.
> I don't see it realistic, but, I would like to simulate it for animation.
> For me it is very beautiful!
>

I recognise the island. It the one mentioned in Shakespeare’s play, “The 
Tempest”.
“…’twixt the green sea and the azured vault...’ ;)

It is strikingly vibrant and unearthly.

How to animate it?
The only thing I can think of, is to find out how animated motion lamps 
work. They had a cylindrical outer and inner part and the inner cylinder 
rotated from the heat of the light. The outer cylinder had transparent 
areas that showed the motion. A quick google did not describe the technique.
Examples:

https://youtu.be/TT3trX6oSjk

You get a short glimpse of the moving part here.

https://www.youtube.com/watch?v=nzUSWjt3PWU



-- 

Regards
     Stephen

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Stephen <mca### [at] aolcom> wrote:

>
> I recognise the island. It the one mentioned in Shakespeare�™s play, “The
> Tempest”.
> “�¦�™twixt the green sea and the azured vault...�™ ;)

It what is written? It is a Devanagari?


> How to animate it?

It is necessary to think. :)

Post a reply to this message

On 4/2/2016 9:10 PM, LanuHum wrote:
> Stephen <mca### [at] aolcom> wrote:
>
>>
>> I recognise the island. It the one mentioned in Shakespeare’s play,
“The
>> Tempest”.
>> “…’twixt the green sea and the azured vault...’ ;)
>
> It what is written? It is a Devanagari?
>
>

No that is corruption. I am posting with thunderbird using Unicode. It 
should be plain English text.

Twixt the green sea and the azured vault

Twixt is old English for between.


>> How to animate it?
>
> It is necessary to think. :)
>

Yes, me too.

I found these. The insides are shown. Look at the pictures.

http://www.smsnoveltiques.com/referencemotionlamps.asp

https://www.realorrepro.com/article/Reproductions-in-motion




-- 

Regards
     Stephen

Post a reply to this message

On 2-4-2016 21:32, Stephen wrote:
> On 4/2/2016 2:56 PM, LanuHum wrote:
>>
>> Long ago in shop I photographed a pattern? (pictures,images?)
>> reproduction.
>> I don't see it realistic, but, I would like to simulate it for animation.
>> For me it is very beautiful!
>>
>
> I recognise the island. It the one mentioned in Shakespeare’s play, “The
> Tempest”.
> “…’twixt the green sea and the azured vault...’ ;)
>
> It is strikingly vibrant and unearthly.
>
> How to animate it?
> The only thing I can think of, is to find out how animated motion lamps
> work. They had a cylindrical outer and inner part and the inner cylinder
> rotated from the heat of the light. The outer cylinder had transparent
> areas that showed the motion. A quick google did not describe the
> technique.
> Examples:
>
> https://youtu.be/TT3trX6oSjk
>
> You get a short glimpse of the moving part here.
>
> https://www.youtube.com/watch?v=nzUSWjt3PWU
>

I may be missing something here, but is animation not very easy? just 
rotate the inner cylinder. Essentially, the whole structure consists of 
two moving semitransparent, superposed, image_maps.


-- 
Thomas

Post a reply to this message

On 4/3/2016 7:54 AM, Thomas de Groot wrote:
>
> I may be missing something here, but is animation not very easy? just
> rotate the inner cylinder. Essentially, the whole structure consists of
> two moving semitransparent, superposed, image_maps.
>
>

Probably not. But it is mumble, mumble years since I have seen one and 
was not sure how the effect was created. I thought that the glass 
cylinders might have been moulded to give local lenses on the inside.

Will the illusion work with computer graphics using planer images?
What sort of masking is needed for the images and what frame rate to 
use? These questions I will need to find an answer to.
I think that this might distract me from Elite Dangerous, for a while. :-)

-- 

Regards
     Stephen

Post a reply to this message

Stephen <mca### [at] aolcom> wrote:
> On 4/3/2016 7:54 AM, Thomas de Groot wrote:
> >
> > I may be missing something here, but is animation not very easy? just
> > rotate the inner cylinder. Essentially, the whole structure consists of
> > two moving semitransparent, superposed, image_maps.
> >
> >
>
> Probably not. But it is mumble,

Yes! Desires differ from opportunities...
:)))))

Post a reply to this message

On 3-4-2016 10:18, Stephen wrote:
> On 4/3/2016 7:54 AM, Thomas de Groot wrote:
>>
>> I may be missing something here, but is animation not very easy? just
>> rotate the inner cylinder. Essentially, the whole structure consists of
>> two moving semitransparent, superposed, image_maps.
>>
>>
>
> Probably not. But it is mumble, mumble years since I have seen one and
> was not sure how the effect was created. I thought that the glass
> cylinders might have been moulded to give local lenses on the inside.

Hmm... that is an interesting approach I had not thought about. Variable 
thickness of the inner cylinder might certainly be an interesting effect.

>
> Will the illusion work with computer graphics using planer images?
> What sort of masking is needed for the images and what frame rate to
> use? These questions I will need to find an answer to.
> I think that this might distract me from Elite Dangerous, for a while. :-)
>

Good. It will keep you from grave mischief in the digital world. I may 
want to explore a bit about superposition of images and such, without 
the animation part. I think that ior and photons should be involved too 
in the end.

-- 
Thomas

Post a reply to this message

Am 02.04.2016 um 22:10 schrieb LanuHum:
> Stephen <mca### [at] aolcom> wrote:
> 
>>
>> I recognise the island. It the one mentioned in Shakespeare’s play, “The
>> Tempest�.
>> “…’twixt the green sea and the azured vault...’ ;)
> 
> It what is written? It is a Devanagari?

To quote from Stephen's post (the message header, to be precise):

----------------------------------------------------------------
Subject: Re: Ocean
Newsgroups: povray.binaries.images
References: <56ffb693$1@news.povray.org>
 <web.56ffcf8542d9a4ac7a3e03fe0@news.povray.org>
From: Stephen <mca### [at] aolcom>
Date: Sat, 2 Apr 2016 20:32:12 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
In-Reply-To: <web.56ffcf8542d9a4ac7a3e03fe0@news.povray.org>
Content-Type: text/plain; charset=utf-8; format=flowed
...
----------------------------------------------------------------

Note the "charset=utf-8".

The web interface to the newsgroups apparently fails to handle character
sets; newsreaders typically display the content properly.

Post a reply to this message

On 4/3/2016 12:20 PM, Thomas de Groot wrote:
> On 3-4-2016 10:18, Stephen wrote:
>> On 4/3/2016 7:54 AM, Thomas de Groot wrote:
>>>
>>> I may be missing something here, but is animation not very easy? just
>>> rotate the inner cylinder. Essentially, the whole structure consists of
>>> two moving semitransparent, superposed, image_maps.
>>>
>>>
>>
>> Probably not. But it is mumble, mumble years since I have seen one and
>> was not sure how the effect was created. I thought that the glass
>> cylinders might have been moulded to give local lenses on the inside.
>
> Hmm... that is an interesting approach I had not thought about. Variable
> thickness of the inner cylinder might certainly be an interesting effect.
>
>>
>> Will the illusion work with computer graphics using planer images?
>> What sort of masking is needed for the images and what frame rate to
>> use? These questions I will need to find an answer to.
>> I think that this might distract me from Elite Dangerous, for a while.
>> :-)
>>
>
> Good. It will keep you from grave mischief in the digital world. I may
> want to explore a bit about superposition of images and such, without
> the animation part. I think that ior and photons should be involved too
> in the end.
>

Proof of concept.
It needs more work on the inner cylinder* and the masking.
It is short and cyclic. Probably better to download it and watch it looping.

https://youtu.be/21Tb8_HIDp8


* Not that there are cylinders, it is planer.


-- 

Regards
     Stephen

Post a reply to this message

Stephen <mca### [at] aolcom> wrote:

>
> Proof of concept.
> It needs more work on the inner cylinder* and the masking.
> It is short and cyclic. Probably better to download it and watch it looping.
>
> https://youtu.be/21Tb8_HIDp8
>
>
> * Not that there are cylinders, it is planer.
>
>
> --
>
> Regards
>      Stephen

This toy can be made so:

#declare Light_waves = texture {pigment {
    agate
    color_map{[0 rgbt<1,1,1,0.9>]
              [1 rgbt<0,0,0,0.9>]}
    scale <1,10,1>
    translate -z * ANIMATION
}
}

#declare All = texture {
    texture {Sea}
    texture {Light_waves}
}

My idea more serious:
1. Create curves.
2. Insert shape keys
3. Use LanuHum,s exporter.
Good?

Post a reply to this message

Attachments:
Download 'idea.jpg' (27 KB)

Preview of image 'idea.jpg'

On 4/4/2016 4:54 PM, LanuHum wrote:
> This toy can be made so:
>
> #declare Light_waves = texture {pigment {
>      agate
>      color_map{[0 rgbt<1,1,1,0.9>]
>                [1 rgbt<0,0,0,0.9>]}
>      scale <1,10,1>
>      translate -z * ANIMATION
> }
> }
>
> #declare All = texture {
>      texture {Sea}
>      texture {Light_waves}
> }
>
> My idea more serious:
> 1. Create curves.
> 2. Insert shape keys
> 3. Use LanuHum,s exporter.
> Good?


Yes good but first one better. ;)

-- 

Regards
     Stephen

Post a reply to this message

Le 16-04-03 04:18, Stephen a écrit :
> On 4/3/2016 7:54 AM, Thomas de Groot wrote:
>>
>> I may be missing something here, but is animation not very easy? just
>> rotate the inner cylinder. Essentially, the whole structure consists of
>> two moving semitransparent, superposed, image_maps.
>>
>>
>
> Probably not. But it is mumble, mumble years since I have seen one and
> was not sure how the effect was created. I thought that the glass
> cylinders might have been moulded to give local lenses on the inside.
>
> Will the illusion work with computer graphics using planer images?
> What sort of masking is needed for the images and what frame rate to
> use? These questions I will need to find an answer to.
> I think that this might distract me from Elite Dangerous, for a while. :-)
>

The inner, rotating, cylinder have transparent and diffuse areas.
The transparent areas can be coloured, as can the diffuse areas.
The light used is usualy a standard light bulb. If the distance between 
the inner and outer cylinders is small, a frosted bulb is used, and a 
clear one if the distance is large. This is to provide softer shading.

It can easily be done with a computer using planar image in several ways.
You can have the shading image with no_image set between the light and 
the image.
You can use back side illumination that replicate the actual device.
You can use a blurred image that is to be layered with the base image.
There are probably other ways to acheive the same effect.

Post a reply to this message

On 4-4-2016 14:58, Stephen wrote:

> Proof of concept.
> It needs more work on the inner cylinder* and the masking.
> It is short and cyclic. Probably better to download it and watch it
> looping.
>
> https://youtu.be/21Tb8_HIDp8

Yes, that looks like it I believe.

-- 
Thomas

Post a reply to this message

On 4/4/2016 10:42 PM, Alain wrote:
>> Will the illusion work with computer graphics using planer images?
>> What sort of masking is needed for the images and what frame rate to
>> use? These questions I will need to find an answer to.
>> I think that this might distract me from Elite Dangerous, for a while.
>> :-)
>>
>
> The inner, rotating, cylinder have transparent and diffuse areas.
> The transparent areas can be coloured, as can the diffuse areas.
> The light used is usualy a standard light bulb. If the distance between
> the inner and outer cylinders is small, a frosted bulb is used, and a
> clear one if the distance is large. This is to provide softer shading.
>

Thanks for the reply, Alain. What you've said makes perfect sense.


> It can easily be done with a computer using planar image in several ways.
> You can have the shading image with no_image set between the light and
> the image.
> You can use back side illumination that replicate the actual device.
> You can use a blurred image that is to be layered with the base image.
> There are probably other ways to acheive the same effect.

Interesting techniques. I used a mask made from the shape of the sea to 
restrict the area that had movement. Some areas of the sea looks fine 
but others look wrong. So I started to make additional masks but my 
image editing s/ware is so old (Paintshop Pro 7) it is too tedious to 
continue.
I am happy to know it can be done, though.


-- 

Regards
     Stephen

Post a reply to this message

El 31/03/16 a las 20:35, Jaime Vives Piqueres escribió:
> P.S.: The foam is still on the making...

    After a lot of failed attempts with different techniques to place the
foam on the crests edges, I figured out the solution would be to use the
proximity macro by Samuel Benge. Here is attached the first try using
Nest_Prox()... still needs work.

--
jaime

Post a reply to this message

Attachments:
Download 'ocean-14.jpg' (134 KB)

Preview of image 'ocean-14.jpg'

On 5-4-2016 12:11, Jaime Vives Piqueres wrote:
> El 31/03/16 a las 20:35, Jaime Vives Piqueres escribió:
>> P.S.: The foam is still on the making...
>
>     After a lot of failed attempts with different techniques to place the
> foam on the crests edges, I figured out the solution would be to use the
> proximity macro by Samuel Benge. Here is attached the first try using
> Nest_Prox()... still needs work.
>

Good thinking Jaime! That is very good looking.

Something I remember from my days at sea is that sometimes, a given part 
of the wave became temporarily (less than a minute) an almost perfect 
surface without irregularities and with a high transparency. Not a hint 
to you but just something I remember, in particular from the North Sea. 
I crossed the Southern Atlantic and criss-crossed the Antarctic waters 
(on the Polarstern) but I do not remember that from over there.

-- 
Thomas

Post a reply to this message

Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> El 01/04/16 a las 22:45, Sven Littkowski escribió:
> > This is the most realistic ocean I have seen so far! Will you
> > publish the scene source code?
>
>    Thanks... of course, sources will be published once I finish fiddling
> with it.
>
> > Just the sky is pink and some dust does not allow to see very far, so
> > it seems.
>
>    Well, the sky is from CIE_Skylight.inc, and yes, I've never been very
> satisfied with the pinkish coloring at horizon. On the first image is
> less noticeable as I lowered the white point to 4000K.
>
>    The dust/haze is on purpose, to hide the fact that the sea is a mesh
> with a finite resolution.
>
> --
> jaime

I'm developing a skylight generator to produce pre-traced image map. Maybe it
can help that.

Post a reply to this message

El 06/04/16 a las 16:23, And escribió:
> I'm developing a skylight generator to produce pre-traced image map.
> Maybe it can help that.

   It could be interesting, indeed. CIE_Skylight.inc has also a problem
where seams between dome triangles are sometimes visible...

   Your generator is POV-Ray SDL or an external program?

--
jaime

Post a reply to this message

Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> El 06/04/16 a las 16:23, And escribi�:
> > I'm developing a skylight generator to produce pre-traced image map.
> > Maybe it can help that.
>
>    It could be interesting, indeed. CIE_Skylight.inc has also a problem
> where seams between dome triangles are sometimes visible...
>
>    Your generator is POV-Ray SDL or an external program?
>
> --
> jaime

POV-Ray SDL. I use many functions() to simulate the ray-tracing of the sky.

Post a reply to this message

El 06/04/16 a las 18:08, And escribió:
> POV-Ray SDL. I use many functions() to simulate the ray-tracing of the sky.

   That's nice... I'm looking forward to it being released.

--
jaime

Post a reply to this message

El 05/04/16 a las 12:11, Jaime Vives Piqueres escribió:
> ... still needs work.

   Well, the proximity pattern is still not what I really need, but gets
close. Unfortunately it really makes the render much slower (x4)...
luckly I'm using a mesh: with an isosurface this would have taken almost
2/3 days.

--
jaime

Post a reply to this message

Attachments:
Download 'ocean-15e.jpg' (101 KB)

Preview of image 'ocean-15e.jpg'

On 7-4-2016 9:17, Jaime Vives Piqueres wrote:
> El 05/04/16 a las 12:11, Jaime Vives Piqueres escribió:
>> ... still needs work.
>
>    Well, the proximity pattern is still not what I really need, but gets
> close. Unfortunately it really makes the render much slower (x4)...
> luckly I'm using a mesh: with an isosurface this would have taken almost
> 2/3 days.
>

This is very close indeed. Less convincing foam close up but in the 
distance it looks very good.

-- 
Thomas

Post a reply to this message

On 4/7/2016 8:17 AM, Jaime Vives Piqueres wrote:
> El 05/04/16 a las 12:11, Jaime Vives Piqueres escribió:
>> ... still needs work.
>
>    Well, the proximity pattern is still not what I really need, but gets
> close. Unfortunately it really makes the render much slower (x4)...
> luckly I'm using a mesh: with an isosurface this would have taken almost
> 2/3 days.
>

That looks good to me.
Sea state 5 or 6, I would guess.
In 2009 Edouard Poor created DF3 proximity pattern macros.
That might be worth a try.


-- 

Regards
     Stephen

Post a reply to this message

On 7-4-2016 10:08, Stephen wrote:
> On 4/7/2016 8:17 AM, Jaime Vives Piqueres wrote:
>> El 05/04/16 a las 12:11, Jaime Vives Piqueres escribió:
>>> ... still needs work.
>>
>>    Well, the proximity pattern is still not what I really need, but gets
>> close. Unfortunately it really makes the render much slower (x4)...
>> luckly I'm using a mesh: with an isosurface this would have taken almost
>> 2/3 days.
>>
>
> That looks good to me.
> Sea state 5 or 6, I would guess.
> In 2009 Edouard Poor created DF3 proximity pattern macros.
> That might be worth a try.
>
>
I was going to suggest Edouard's macros too. I prefer them to Sam's and 
believe them to be faster. Advantage is that the pattern is calculated 
and saved to file before render.

-- 
Thomas

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Am 07.04.2016 um 09:17 schrieb Jaime Vives Piqueres:
> El 05/04/16 a las 12:11, Jaime Vives Piqueres escribió:
>> ... still needs work.
> 
>   Well, the proximity pattern is still not what I really need, but gets
> close. Unfortunately it really makes the render much slower (x4)...
> luckly I'm using a mesh: with an isosurface this would have taken almost
> 2/3 days.

I'm wondering: Presuming the foam is a texture (rather than a media
effect), shouldn't a slope pattern do the job?

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El 07/04/16 a las 09:58, Thomas de Groot escribió:
> This is very close indeed. Less convincing foam close up but in the
> distance it looks very good.

   That's another matter... the foam texture is not very good. I find it
very difficult to get a convincing one.

--
jaime

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El 07/04/16 a las 10:08, Stephen escribió:
> That looks good to me. Sea state 5 or 6, I would guess.

   Thanks!

> In 2009 Edouard Poor created DF3 proximity pattern macros. That might
> be worth a try.

   Thanks, I will try... also the proximity pattern included on hgpovray
(I just found about it).

--
jaime

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El 07/04/16 a las 13:35, clipka escribió:
> I'm wondering: Presuming the foam is a texture (rather than a media
> effect), shouldn't a slope pattern do the job?
>

   Yes, it is a texture (well, a pattern for the combined water/foam
texture map). And yes, that's what I thought at first, so I tried a
slope y with altitude, but didn't work very well... maybe my fault at
implementing it, but then I thought about the proximity pattern thing,
so I abandoned the slope approach.

--
jaime

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Am 07.04.2016 um 13:47 schrieb Jaime Vives Piqueres:
> El 07/04/16 a las 13:35, clipka escribió:
>> I'm wondering: Presuming the foam is a texture (rather than a media
>> effect), shouldn't a slope pattern do the job?
>>
> 
>   Yes, it is a texture (well, a pattern for the combined water/foam
> texture map). And yes, that's what I thought at first, so I tried a
> slope y with altitude, but didn't work very well... maybe my fault at
> implementing it, but then I thought about the proximity pattern thing,
> so I abandoned the slope approach.

I wouldn't use altitude, just the plain slope.

Given that the slope pattern is a lot faster than any proximity pattern,
I think it should be worth another try.

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El 07/04/16 a las 15:52, clipka escribió:
> I wouldn't use altitude, just the plain slope.
>
> Given that the slope pattern is a lot faster than any proximity
> pattern, I think it should be worth another try.
>

   But just plain "slope y" shows foam also on "valley" parts of the
surface, not only on the crests. Or are you suggestion another approach?

--
jaime

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Am 07.04.2016 um 16:26 schrieb Jaime Vives Piqueres:
> El 07/04/16 a las 15:52, clipka escribió:
>> I wouldn't use altitude, just the plain slope.
>>
>> Given that the slope pattern is a lot faster than any proximity
>> pattern, I think it should be worth another try.
>>
> 
>   But just plain "slope y" shows foam also on "valley" parts of the
> surface, not only on the crests. Or are you suggestion another approach?

From what I see the waves aren't sinusoidal, but have "sharp" peaks, so
a high slope should be the proper indicator.

Then again, I must concede that this idea crumbles if the peaks aren't
perfectly sharp after all.


Let's take a step backward:

What you want is foam at the crests, i.e. near local maxima.

Local maxima can be identified by a zero 1st derivative (aka slope) and
negative 2nd derivative (aka curvature).

It should be possible to analyze the f_ridged_mf() function in order to
construct the 1st and 2nd derivative functions, and use the resulting
functions as a basis for a foam pattern. (If you want to avoid function
analysis, you could still design functions for the slope and curvature
that effectively take samples from the original function.)

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El 07/04/16 a las 16:54, clipka escribió:
> Then again, I must concede that this idea crumbles if the peaks
> aren't perfectly sharp after all.

   Well, the function heighfield I'm using is surely having flat
triangles there. For perfectly sharp crests I guess I would have to use
crazy resolutions.

> Let's take a step backward:
>
> What you want is foam at the crests, i.e. near local maxima.
>
> Local maxima can be identified by a zero 1st derivative (aka slope)
> and negative 2nd derivative (aka curvature).
>
> It should be possible to analyze the f_ridged_mf() function in order
> to construct the 1st and 2nd derivative functions, and use the
> resulting functions as a basis for a foam pattern. (If you want to
> avoid function analysis, you could still design functions for the
> slope and curvature that effectively take samples from the original
> function.)
>

   :O ...that's a too advanced approach for me: I barely passed maths at
school.

--
jaime

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Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> El 07/04/16 a las 16:54, clipka escribió:
> > Then again, I must concede that this idea crumbles if the peaks
> > aren't perfectly sharp after all.
>
>    Well, the function heighfield I'm using is surely having flat
> triangles there. For perfectly sharp crests I guess I would have to use
> crazy resolutions.

If you test the function instead of the height field, that won't be a problem.

> > Let's take a step backward:
> >
> > What you want is foam at the crests, i.e. near local maxima.
> >
> > Local maxima can be identified by a zero 1st derivative (aka slope)
> > and negative 2nd derivative (aka curvature).
> >
> > It should be possible to analyze the f_ridged_mf() function in order
> > to construct the 1st and 2nd derivative functions, and use the
> > resulting functions as a basis for a foam pattern. (If you want to
> > avoid function analysis, you could still design functions for the
> > slope and curvature that effectively take samples from the original
> > function.)
> >
>
>    :O ...that's a too advanced approach for me: I barely passed maths at
> school.

My instinct would be to avoid the analysis approach, and do sampling on the
original function.  That doesn't take a lot of sophisticated math.  I can't even
remember the chain rule without looking it up (and the last time I did so was,
like, 2005), but I have used sampling to estimate normals on a form based on
parametric functions.  I did this for the smooth triangles of the elliptical
toroids in RoundEdge.  Normals, of course, can be easily converted to slopes.

Sampling won't get you the 2nd derivative, but it will tell you whether it's
positive or negative, which is enough for clipka's plan.

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El 08/04/16 a las 06:45, Cousin Ricky escribió:
> My instinct would be to avoid the analysis approach, and do sampling
> on the original function.  That doesn't take a lot of sophisticated
> math.  I can't even remember the chain rule without looking it up
> (and the last time I did so was, like, 2005), but I have used
> sampling to estimate normals on a form based on parametric functions.
> I did this for the smooth triangles of the elliptical toroids in
> RoundEdge.  Normals, of course, can be easily converted to slopes.
>

   I'm still trying to grasp the concept of "sampling a function"... how
I would do that? With another function? If someone can please post a
simple example...

--
jaime

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Am 08.04.2016 um 09:49 schrieb Jaime Vives Piqueres:
> El 08/04/16 a las 06:45, Cousin Ricky escribió:
>> My instinct would be to avoid the analysis approach, and do sampling
>> on the original function.  That doesn't take a lot of sophisticated
>> math.  I can't even remember the chain rule without looking it up
>> (and the last time I did so was, like, 2005), but I have used
>> sampling to estimate normals on a form based on parametric functions.
>> I did this for the smooth triangles of the elliptical toroids in
>> RoundEdge.  Normals, of course, can be easily converted to slopes.
>>
> 
>   I'm still trying to grasp the concept of "sampling a function"... how
> I would do that? With another function? If someone can please post a
> simple example...

// Base function
#declare Fn = function(x,y) { /* whatever */ }

#declare EPSILON = 1e-6;

// Approximate first derivatives along the x and y axes
#declare Fn1X = function(x,y)
  { (Fn(x+EPSILON,y)-Fn(x-EPSILON,y))/EPSILON }
#declare Fn1Y = function(x,y)
  { (Fn(x,y+EPSILON)-Fn(x,y-EPSILON))/EPSILON }

// Approximate second derivatives along the x and y axes
#declare Fn2X = function(x,y)
  { (Fn1X(x+EPSILON,y)-Fn1X(x-EPSILON,y))/EPSILON }
#declare Fn2Y = function(x,y)
  { (Fn1Y(x,y+EPSILON)-Fn1Y(x,y-EPSILON))/EPSILON }

Note how the first derivative functions effectively "sample" the base
function at two points, and the second derivative functions do the same
for the first derivative functions.

(Also note that this formulation of the second derivative is
inefficient, as it results in sampling the base function four times:
Once at an offset of -2*EPSILON, once at an offset of +2*EPSILON, and
twice at an offset of 0; computing the second derivative directly from
samples of the base function could reduce this to three samples.)

The slope can then be computed from the first derivatives, and the
curvature from the second derivatives, both of which I leave as an
exercise to the reader (academic parlance for "I don't have the patience
to figure it out" ;))

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On 04/08/2016 02:24 PM, clipka wrote:
> Am 08.04.2016 um 09:49 schrieb Jaime Vives Piqueres:
>> El 08/04/16 a las 06:45, Cousin Ricky escribió:
>>> My instinct would be to avoid the analysis approach, and do sampling
>>> on the original function.  That doesn't take a lot of sophisticated
>>> math.  I can't even remember the chain rule without looking it up
>>> (and the last time I did so was, like, 2005), but I have used
>>> sampling to estimate normals on a form based on parametric functions.

>>> I did this for the smooth triangles of the elliptical toroids in
>>> RoundEdge.  Normals, of course, can be easily converted to slopes.
>>>
>>
>>   I'm still trying to grasp the concept of "sampling a function"... ho
w
>> I would do that? With another function? If someone can please post a
>> simple example...
> 
> // Base function
> #declare Fn = function(x,y) { /* whatever */ }
> 
> #declare EPSILON = 1e-6;
> 
> // Approximate first derivatives along the x and y axes
> #declare Fn1X = function(x,y)
>   { (Fn(x+EPSILON,y)-Fn(x-EPSILON,y))/EPSILON }
> #declare Fn1Y = function(x,y)
>   { (Fn(x,y+EPSILON)-Fn(x,y-EPSILON))/EPSILON }
> 
> // Approximate second derivatives along the x and y axes
> #declare Fn2X = function(x,y)
>   { (Fn1X(x+EPSILON,y)-Fn1X(x-EPSILON,y))/EPSILON }
> #declare Fn2Y = function(x,y)
>   { (Fn1Y(x,y+EPSILON)-Fn1Y(x,y-EPSILON))/EPSILON }
> 
	There's a missing (2*..) in all formulas. It should be:

#declare Fn1X = function(x,y)
  { (Fn(x+EPSILON,y)-Fn(x-EPSILON,y))/(2*EPSILON) }

	and the same for the others. OTOH if all you want is to know whether it
is positive or negative then you can drop the whole "/EPSILON".

		Jerome
-- 
mailto:jeb### [at] freefr
http://jeberger.free.fr
Jabber: jeb### [at] jabberfr

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Am 08.04.2016 um 19:21 schrieb Jérôme M. Berger:

> 	There's a missing (2*..) in all formulas. It should be:
> 
> #declare Fn1X = function(x,y)
>   { (Fn(x+EPSILON,y)-Fn(x-EPSILON,y))/(2*EPSILON) }

Indeed. My bad.

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Hi Jaime,

just following up: how far are you with this amazing scene? Still
interested in the scene code as I want to use your way to create a
realistic ocean surface in some maritime scenes.

Sven





On 02.04.2016 02:36, Jaime Vives Piqueres wrote:
> El 01/04/16 a las 22:45, Sven Littkowski escribió:
>> This is the most realistic ocean I have seen so far! Will you
>> publish the scene source code?
> 
>   Thanks... of course, sources will be published once I finish fiddling
> with it.
> 
>> Just the sky is pink and some dust does not allow to see very far, so
>> it seems.
> 
>   Well, the sky is from CIE_Skylight.inc, and yes, I've never been very
> satisfied with the pinkish coloring at horizon. On the first image is
> less noticeable as I lowered the white point to 4000K.
> 
>   The dust/haze is on purpose, to hide the fact that the sea is a mesh
> with a finite resolution.
> 
> -- 
> jaime
>

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El 23/02/17 a las 16:42, Sven Littkowski escribió:
> Hi Jaime,
>
> just following up: how far are you with this amazing scene? Still
> interested in the scene code as I want to use your way to create a
> realistic ocean surface in some maritime scenes.

   I'm sorry but I've not worked on it since then... it's been on my
"pending to clean and publish" folder for months. Let's see if I can do
that this weekend...

--
Jaime

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That would be wonderful. I am looking forward, and I am sure, many
others do, too.   :-)






On 23.02.2017 16:51, Jaime Vives Piqueres wrote:
> El 23/02/17 a las 16:42, Sven Littkowski escribió:
>> Hi Jaime,
>>
>> just following up: how far are you with this amazing scene? Still
>> interested in the scene code as I want to use your way to create a
>> realistic ocean surface in some maritime scenes.
> 
>   I'm sorry but I've not worked on it since then... it's been on my
> "pending to clean and publish" folder for months. Let's see if I can do
> that this weekend...
> 
> -- 
> Jaime
> 
>

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El 23/02/17 a las 22:51, Jaime Vives Piqueres escribió:
> El 23/02/17 a las 16:42, Sven Littkowski escribió:
>> Hi Jaime,
>>
>> just following up: how far are you with this amazing scene? Still
>> interested in the scene code as I want to use your way to create a
>> realistic ocean surface in some maritime scenes.
>
> I'm sorry but I've not worked on it since then... it's been on my
> "pending to clean and publish" folder for months. Let's see if I can
>  do that this weekend...
>

   Hmmm... not much luck this weekend: seems I made a mess of the code
with later tests, and I'm still trying to get something as good as the
images I posted here. :( ...will keep working on it this week if I can
find some free time.

--
jaime

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