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Strand rendering

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Strand rendering

Post Tue Oct 25, 2011 5:10 pm

Hi!
I would like to know how to setup the strand rendering with hair particule system on a mesh ( ex: carpet with long hair). And what about the width fade button ? Please need help... :cry:

Olivier Boscournu __ riofranco design  Montpellier _ France   http://www.olivier-boscournu.com/

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Rio
 
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Re: Strand rendering

Post Wed Oct 26, 2011 9:16 pm

Rio wrote:Hi!
I would like to know how to setup the strand rendering with hair particule system on a mesh ( ex: carpet with long hair). And what about the width fade button ? Please need help... :cry:


it works in the same way as for Blender except that yafaray does not support fade shading (afaik) or child particles. So you can try 3dmodelling strands by hand, 5 to 10 different strands (like subdivided planes changing shape and/or rotation to get some random effect) and then make them a group in a separated layer. Create a particle system and use that group as source object with "Pick Random" box checked. Yafaray will use instancing for the particle system.

http://www.yafaray.org/community/forum/viewtopic.php?f=29&t=4208&start=13

http://www.yafaray.org/phpBB3/download/file.php?id=5252&mode=view

http://www.yafaray.org/phpBB3/download/file.php?id=5251&mode=view

http://www.yafaray.org/community/forum/viewtopic.php?f=15&t=3948&start=9


... Or just try classic hair strands and change Brownian value (Particle System: Advanced -> Physics) to make it looks more natural. The exporter for Blender 2.6 support strand rendering; Root, Tip and Shape define the type of a strand. But exporting strands particles take more time than the previous method because yafaray creates every particle individually ... and with no instancing.
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strands.png

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condar
 
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Re: Strand rendering

Post Wed Nov 16, 2011 6:51 am

Don't know where to place this stuff, so let it be here. I've made a quick fur test in 012 after condar's advice #1 about strand modeling and here's result.
Attachments
covertest2.jpg
covertest.jpg
suomi
 
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Re: Strand rendering

Post Wed Nov 16, 2011 9:36 am

Suomi,
This is the best carpet I have ever seen! :shock:
Can you share the particle system and material settings?
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Re: Strand rendering

Post Wed Nov 16, 2011 10:00 am

Of course. :) Here the .blend without a sofa. Materials and lights are untouched. Blender 2.59, Yafaray 0.1.2.
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cover_test.blend.zip
(821.23 KiB) Downloaded 1045 times
suomi
 
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Re: Strand rendering

Post Wed Nov 16, 2011 5:17 pm

:D
Suomi,
Thank you very much for your kindness.
I went to see your posted images, and I became absolutly impressed.
Your works are very nice.
Keep posting.
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Re: Strand rendering

Post Wed Nov 16, 2011 7:18 pm

Hi all!
Thanks you so much Condar & Suomi ! Great replies and works ! Actually I was looking for how to setup the fade shading, but Condar told Yafa doesn't support it yet ! I hope it will be possible in the near future ! One more time, thanks ! :D

Olivier Boscournu __ riofranco design  Montpellier _ France   http://www.olivier-boscournu.com/

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Rio
 
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Re: Strand rendering

Post Thu Nov 17, 2011 1:59 am

Is there any possibility, that using the png texture with transparency on a base strand meshes would be the answer for your question?
suomi
 
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Re: Strand rendering

Post Thu Nov 17, 2011 12:33 pm

Maybe, I am not yet mastered the topic, can you show me that please?

Olivier Boscournu __ riofranco design  Montpellier _ France   http://www.olivier-boscournu.com/

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Re: Strand rendering

Post Fri Nov 18, 2011 6:24 am

suomi wrote:Is there any possibility, that using the png texture with transparency on a base strand meshes would be the answer for your question?


that's the way I use instanced hair with Yafaray BUT there is a bug with transparency and fake shadows. Yafaray will crash with transparent instanced objects using Transparent shadows/fake shadows (I don't know why). Any other option for transparent materials will work fine... ;)

EDIT: I didn't note that "Child particles" are supported now :mrgreen:

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condar
 
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Re: Strand rendering

Post Fri Nov 18, 2011 12:46 pm

I think that has been fixed too.

I'm pretty sure turning on Transparent Shadows results in exporting objects as mesh instead of instance.
Not sure how it works but it seems to.
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stoneage
 
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Re: Strand rendering

Post Fri Nov 18, 2011 3:04 pm

stoneage wrote:I think that has been fixed too.

I'm pretty sure turning on Transparent Shadows results in exporting objects as mesh instead of instance.
Not sure how it works but it seems to.


This hasn't been fixed in yafaray engine, but i have coded a "workaround" for that situation into the
exporter, so if "transparent shadows" option is on -> no instanced objects. (See io/yaf_object.py
from line 185 -> it is documented there too).

Btw. there are some more workarounds in exporter code e.g. for border rendering, mostly coded in
to prevent crashing the yafaray render engine.
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Re: Strand rendering

Post Fri Nov 25, 2011 10:02 am

Suomi,

I realized that you were using photon mapping on an open scene!
I changed to path tracing and time has increased a lot without much gain in detail and even higher noise.
I assume that when using particles photon mapping is more suitable even for open scenes.
From your experience can you all agree with this statement?
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Re: Strand rendering

Post Fri Nov 25, 2011 11:16 am

Arquitecto wrote:Suomi,

I realized that you were using photon mapping on an open scene!
I changed to path tracing and time has increased a lot without much gain in detail and even higher noise.
I assume that when using particles photon mapping is more suitable even for open scenes.
From your experience can you all agree with this statement?


Indirect light calculated by path tracing or photon mapping + FG is only a component of the final result, which is direct lighting + indirect lighting. Fact is, in some scenes, the indirect lighting component is very small, so it does not make much difference whether you use it or not. Besides, indirect lighting accumulates not on the specular component but only on the diffuse component of materials.
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Re: Strand rendering

Post Mon Nov 28, 2011 10:09 am

Thanks Samo. :)
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