[Sidefx-houdini-list] Linear Workflow

Andy Nicholas andy at andynicholas.com
Wed Aug 25 19:57:49 EDT 2010


Thanks a lot Mario, that sounds like exactly what I'm after. I'll check it out.

Cheers,
Andy



On 25 Aug 2010, at 20:07, Mario Marengo <mario at axyzfx.com> wrote:

> In the Mantra ROP, try setting "Color Space" (vm_colorspace) to "Gamma 2.2". 
> This parameter is now always exposed in H11. It should help with the bottom-
> end noisiness (it biases the sampling importance so the dark stuff gets some 
> extra love).
> 
> 
> On Wednesday 25 August 2010 02:52:54 pm Andy Nicholas wrote:
>> Hi guys,
>> We've just started a job in Houdini and we're trying to use a linear
>> colour workflow. With the test I'm doing at the moment, I don't have any
>> textures, it's all pure lighting and shader models. I've got the Color
>> Correction gamma setting at 2.2 which I believe is the correct setting as
>> it visually matches what we do in XSI when we enable colour management.
>> 
>> The problem is that we're having a few issues with generating glossy
>> reflections because noise that wasn't visible before, now shows up a
>> treat, even with a large number of samples.
>> 
>> This is partly because the objects I'm reflecting are quite small, so in a
>> way, I'm not surprised I'm getting some noise. The issue is that before
>> using colour management, this wouldn't have been visible. On a black
>> background typically some of the noisy pixel values are only at around
>> 0.0002, but they still show up as little grey splats on the image.
>> 
>> I've been doing a few tests, and while I get noisier results in mental ray
>> (using XSI with colour management enabled), it generally isn't as bad as
>> I'm seeing in Mantra.
>> 
>> So my simple question is, have any of you guys run into similar problems,
>> and if so, what strategies did you use to work around this issue? (or
>> alternatively, are we just doing something stupid?!)
>> 
>> Thanks,
>> 
>> Andy
>> 
>> 
>> 
>> 
>> 
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> 
> -- 
> ......................................................................
> Mario Marengo                                  mailto:mario at axyzfx.com
> AXYZ ANIMATION                                 http://www.axyzfx.com
> ......................................................................
> 



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