POV-Ray : Newsgroups : povray.binaries.images : A head full of hair : Re: A head full of hair Server Time
1 Dec 2021 17:12:43 EST (-0500)
  Re: A head full of hair  
From: Thomas de Groot
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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