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18 Oct 2021 16:44:21 EDT (-0400)
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From: Thomas de Groot
Subject: A head full of hair
Date: 21 Sep 2021 08:24:40
Message: <6149cf08@news.povray.org>
Following an old discussion in 2014:
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452&moff=21

I took up Robert McGregor's code to see how it could be tweaked to 
obtain a nice haircut. 10000 hairs were planted here. To give a rough 
approximation: parsing took about 10 minutes and complete (stochastic) 
render about half an hour with an i5 machine (Win10; Pov version 3.8). 
The small highlights on the hairs resulted from a combination 
normal/finish choices.

-- 
Thomas


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From: Bald Eagle
Subject: Re: A head full of hair
Date: 21 Sep 2021 15:05:00
Message: <web.614a2c84467a8aa71f9dae3025979125@news.povray.org>
I sense a Chia Pet thread beginning sometime in the future...

https://www.chia.com/


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From: Samuel B 
Subject: Re: A head full of hair
Date: 21 Sep 2021 20:50:00
Message: <web.614a7d06467a8aa7cb705ca46e741498@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Following an old discussion in 2014:
>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452
&moff=21
>
> I took up Robert McGregor's code to see how it could be tweaked to
> obtain a nice haircut. 10000 hairs were planted here. To give a rough
> approximation: parsing took about 10 minutes and complete (stochastic)
> render about half an hour with an i5 machine (Win10; Pov version 3.8).
> The small highlights on the hairs resulted from a combination
> normal/finish choices.

Hey, a fellow i5 owner :) I've got a 6500 here. It's a really good chip.

Ten minutes of parsing seems a little steep. Is the code having to evaluate
every triangle, or just the scalp when choosing to place a hair? And I know
sphere_sweeps can be pretty slow on their own, but I thought they just impacted
the render time. Thirty minutes of render time doesn't seem as terrible as it
could be, but it's still a little high.

Did I ever post my experiments with hair? I was using an .obj-to-.pov converter
and trying to grow hair from a mesh. The way I had it set up was if a triangle
was too small it only had a small chance to grow a hair, otherwise it would try
to grow a certain number of hairs for a given triangle's area. I think I was
using strings of cones though, and not sphere_sweeps.

Sam

P.S. Thanks for reminding me of Wallace and Gromit. It's a great series. Just
watched A Close Shave. What a gem of a flick :D


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From: Thomas de Groot
Subject: Re: A head full of hair
Date: 22 Sep 2021 02:38:15
Message: <614acf57$1@news.povray.org>
Op 21/09/2021 om 21:03 schreef Bald Eagle:
> I sense a Chia Pet thread beginning sometime in the future...
> 
> https://www.chia.com/
> 
> 

Oh LOL! Donald T is absolutely looking better! :-0

-- 
Thomas


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From: Thomas de Groot
Subject: Re: A head full of hair
Date: 22 Sep 2021 03:08:56
Message: <614ad688$1@news.povray.org>
Op 22/09/2021 om 02:47 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Following an old discussion in 2014:
>>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452
> &moff=21
>>
>> I took up Robert McGregor's code to see how it could be tweaked to
>> obtain a nice haircut. 10000 hairs were planted here. To give a rough
>> approximation: parsing took about 10 minutes and complete (stochastic)
>> render about half an hour with an i5 machine (Win10; Pov version 3.8).
>> The small highlights on the hairs resulted from a combination
>> normal/finish choices.
> 
> Hey, a fellow i5 owner :) I've got a 6500 here. It's a really good chip.
> 
<grin> I have an i5 8250 and an i7 8750 here. For some arcane and 
absolutely trivial reasons, I am using the i5 more than the i7, but 
there it is. :-)

> Ten minutes of parsing seems a little steep. Is the code having to evaluate
> every triangle, or just the scalp when choosing to place a hair? And I know
> sphere_sweeps can be pretty slow on their own, but I thought they just impacted
> the render time. Thirty minutes of render time doesn't seem as terrible as it
> could be, but it's still a little high.
> 
Not sure as I have not been monitoring closely what is going on, I guess 
it is the building of the individual mesh2 hairs which sums up. In a 
next run , I shall save/read the hair meshes and that goes faster in the 
end imo. But, not trivial, I had the laptop battery in "best battery 
life" mode; "best performance" mode is certainly faster indeed.

> Did I ever post my experiments with hair? I was using an .obj-to-.pov converter
> and trying to grow hair from a mesh. The way I had it set up was if a triangle
> was too small it only had a small chance to grow a hair, otherwise it would try
> to grow a certain number of hairs for a given triangle's area. I think I was
> using strings of cones though, and not sphere_sweeps.
> 
I don't remember, but that looks interesting, especially the approach 
using triangle sizes. I had not thought of that aspect. I simply used a 
simple trace() function on the skullcap from randomly generated points 
on an external sphere. Pretty fast by itself.

> Sam
> 
> P.S. Thanks for reminding me of Wallace and Gromit. It's a great series. Just
> watched A Close Shave. What a gem of a flick :D
> 
Oh yes, I love them. I was reminded of the scene showing Wallace tasting 
a piece of Moon (on toast) and musing: "Wensleydale?"
> 

-- 
Thomas


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From: Thomas de Groot
Subject: Re: A head full of hair
Date: 22 Sep 2021 08:07:28
Message: <614b1c80@news.povray.org>
Op 22-9-2021 om 09:08 schreef Thomas de Groot:
> Op 22/09/2021 om 02:47 schreef Samuel B.:
>> Thomas de Groot <tho### [at] degrootorg> wrote:
>>> Following an old discussion in 2014:
>>>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452

>>>
>> &moff=21
>>>
>>> I took up Robert McGregor's code to see how it could be tweaked to
>>> obtain a nice haircut. 10000 hairs were planted here. To give a rough
>>> approximation: parsing took about 10 minutes and complete (stochastic)
>>> render about half an hour with an i5 machine (Win10; Pov version 3.8).
>>> The small highlights on the hairs resulted from a combination
>>> normal/finish choices.
>>
>> Hey, a fellow i5 owner :) I've got a 6500 here. It's a really good chip.
>>
> <grin> I have an i5 8250 and an i7 8750 here. For some arcane and 
> absolutely trivial reasons, I am using the i5 more than the i7, but 
> there it is. :-)
> 
>> Ten minutes of parsing seems a little steep. Is the code having to 
>> evaluate
>> every triangle, or just the scalp when choosing to place a hair? And I 
>> know
>> sphere_sweeps can be pretty slow on their own, but I thought they just 
>> impacted
>> the render time. Thirty minutes of render time doesn't seem as 
>> terrible as it
>> could be, but it's still a little high.
>>
> Not sure as I have not been monitoring closely what is going on, I guess 
> it is the building of the individual mesh2 hairs which sums up. In a 
> next run , I shall save/read the hair meshes and that goes faster in the 
> end imo. But, not trivial, I had the laptop battery in "best battery 
> life" mode; "best performance" mode is certainly faster indeed.
> 
Just additional info: with laptop connected to the electricity socket 
and on "best performance", parsing while writing away the mesh2 hairs 
(converted by meshmaker.inc) to files, took about 6 minutes, while total 
render time was 22 minutes.
Reading the mesh2 files parsed in 41 seconds, and total render time took 
17 minutes.

In all cases, stochastic settings were: +am3 +a0.01 +ac0.90 +r3, with 
+wt7 for the number of threads to be used.

-- 
Thomas


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From: jr
Subject: Re: A head full of hair
Date: 22 Sep 2021 09:05:00
Message: <web.614b28f3467a8aa75e0fed26cde94f1@news.povray.org>
hi,

Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 21/09/2021 om 21:03 schreef Bald Eagle:
> > I sense a Chia Pet thread beginning sometime in the future...
> > ...
>
> Oh LOL! Donald T is absolutely looking better! :-0

fwiw, I have named your v nice model "Peter Punk".  :-)

(there's a longtime Slackware contributor who goes by "Piter Punk", and the name
came to mind when I saw the superb render)


regards, jr.


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From: Thomas de Groot
Subject: Re: A head full of hair
Date: 22 Sep 2021 09:28:25
Message: <614b2f79@news.povray.org>
Op 22-9-2021 om 15:00 schreef jr:
> hi,
> 
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 21/09/2021 om 21:03 schreef Bald Eagle:
>>> I sense a Chia Pet thread beginning sometime in the future...
>>> ...
>>
>> Oh LOL! Donald T is absolutely looking better! :-0
> 
> fwiw, I have named your v nice model "Peter Punk".  :-)
> 
Great! I shall keep the name for later renders.

> (there's a longtime Slackware contributor who goes by "Piter Punk", and the name
> came to mind when I saw the superb render)
> 

Ah! The Brasilian guy? His hair is/was a bit shorter.
> 
> regards, jr.
> 


-- 
Thomas


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From: Alain Martel
Subject: Re: A head full of hair
Date: 22 Sep 2021 12:49:18
Message: <614b5e8e$1@news.povray.org>
Le 2021-09-21 à 08:24, Thomas de Groot a écrit :
> Following an old discussion in 2014:
>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452&moff=21

> 
> 
> I took up Robert McGregor's code to see how it could be tweaked to 
> obtain a nice haircut. 10000 hairs were planted here. To give a rough 
> approximation: parsing took about 10 minutes and complete (stochastic) 
> render about half an hour with an i5 machine (Win10; Pov version 3.8). 
> The small highlights on the hairs resulted from a combination 
> normal/finish choices.
> 

What a nice hay ball hair do 😊


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From: Thomas de Groot
Subject: Re: A head full of hair
Date: 23 Sep 2021 02:28:06
Message: <614c1e76@news.povray.org>
Op 22/09/2021 om 18:49 schreef Alain Martel:
> Le 2021-09-21 à 08:24, Thomas de Groot a écrit :
>> Following an old discussion in 2014:
>>
http://news.povray.org/povray.binaries.images/thread/%3Cweb.52dff97746aac96b7a3e03fe0@news.povray.org%3E/?mtop=391452&moff=21

>>
>>
>> I took up Robert McGregor's code to see how it could be tweaked to 
>> obtain a nice haircut. 10000 hairs were planted here. To give a rough 
>> approximation: parsing took about 10 minutes and complete (stochastic) 
>> render about half an hour with an i5 machine (Win10; Pov version 3.8). 
>> The small highlights on the hairs resulted from a combination 
>> normal/finish choices.
>>
> 
> What a nice hay ball hair do 😊

Thanks! I would hate to take a comb through it... :-0

-- 
Thomas


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