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 Post subject: Mr renders only a fraction of hairs
PostPosted: 11 May 2012, 13:50 
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Joined: 06 Jun 2009, 14:01
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I tried to search the forum for post regarding this issue but:

"The following words in your search query were ignored because they are too common words: hair render."

Very helpful for a CG forum.... :p

Anyway, I noticed mental ray and vray render only a fraction of the displayed render hair, or the number of displayed render hair is incorrect. This happens in 2012 as well in 2013. No cutmap or density map applied.
Attachment:
hair_problem.jpg
hair_problem.jpg [ 123.11 KiB | Viewed 523 times ]


Is there any parameter that could limit the number of rendered hair other than in the hair operator?
Testscene is a simple poly sphere with default hair-OP and mr hairshader.

Achim

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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 11 May 2012, 15:33 
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Joined: 09 Jun 2009, 15:45
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it is probably the low antialias value, try to crank it up.


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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 11 May 2012, 19:22 
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Maximus wrote:
it is probably the low antialias value, try to crank it up.


I tried that already, doesn´t help. Also it´s the same with vray.

Achim

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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 11 May 2012, 20:57 
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Seems to me that it's the hairs on the back side of the sphere are the ones not showing up.
Switch the view to constant or shaded or hidden line removal.

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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 12 May 2012, 12:51 
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xsisupport wrote:
Seems to me that it's the hairs on the back side of the sphere are the ones not showing up.
Switch the view to constant or shaded or hidden line removal.



Oops, well in this case you´re right, my fault. I was too quick preparing the screenshot.
The original problem is this:

Attachment:
hair multiplicity.jpg
hair multiplicity.jpg [ 87.34 KiB | Viewed 431 times ]


This is a vray rendering. There seem to be some values of the multiplicity parameter that causes hair to disappear in the rendering. MR tends to crash when I´m fiddeling around with the multiplicity value, having a render region open.

Achim

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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 12 May 2012, 14:23 
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Hair multiplicity shows even more strange behaviors.
I noticed the fur I was creating startet to get patchy and irregular once I turned up the multiplicity and the splay values, which is only partly related to the vray rendering error.
Attachment:
strand_offset01.jpg
strand_offset01.jpg [ 227.72 KiB | Viewed 414 times ]


As you can see, a part of the strands gets shiftet in X.
I tried with a new scene:
Attachment:
strand_offset2.jpg
strand_offset2.jpg [ 121.77 KiB | Viewed 414 times ]

As soon as you start combing the strands, the modified strands shift with the splay at root value, strangely only in one direction. Also the length of the strands seems to get modified unwantedly.


Until I find a solutlion to this, I will for the first time not be able to finish a project in SI, since it´s almost impossible to create dense fur without using the strand multiplier.


Achim

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 Post subject: Re: Mr renders only a fraction of hairs
PostPosted: 19 May 2012, 18:04 
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So I´m the only one experiencing this problem?

Achim

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