[Sidefx-houdini-list] H13 Linear lighting/rendering

Jordi Bares jordibares at gmail.com
Fri Nov 22 05:22:10 EST 2013


On those very strange cases, treat the texture as linear, do your special thing on the shader should work like a charm.

Jordi Bares
jordibares at gmail.com

On 22 Nov 2013, at 07:57, jason slabber <jason.slabber at gmail.com> wrote:

> Hey Peter
> 
> Have you brought this up with SESI?
> Just wondering cause we would also like to have our own control
> over texture colorspace. Not just auto and linear, seems a bit limiting...
> 
> J
> 
> 
> On Thu, Nov 21, 2013 at 7:32 PM, Peter Bowmar <pbowmar at gmail.com> wrote:
> 
>> Hi Craig,
>> 
>> Basically Houdini assumes non-8 bit file formats are encoded sRGB so
>> it linearizes them (gamma .4545) on ingestion via (for example) the
>> vex texture() call. It assumes 16/32 bit are linear (gamma 1 as you
>> say) and uses them straight up.
>> 
>> I think it's very useful for the home user or smaller studio but we
>> apply LUTs to everything and control via pipeline what textures are
>> encoded as (displacement for example might be 8 bit but linear, though
>> that's unusual) so SESI have added some env vars to turn it all off if
>> you want to manage it yourself.
>> 
>> However, in a nutshell, yes, leave your viewer at gamma 2.2 since
>> renders will be "linear" i.e. gamma 1.0 internally.
>> 
>> Cheers,
>> 
>> Peter B
>> 
>> On 21 November 2013 09:05, Craig Hoffman <craigleehoffman at aol.com> wrote:
>>> 
>>> I read this in the H13 docs:
>>> 
>>> Linear color workflow
>>> 
>>> 
>>> Houdini is now set up to work in a linear color space/gamma of 2.2 by
>> default.
>>> 
>>> VEX texture functions that work on 8-bit images will now convert the
>> images from sRGB colorspace to linear. You can override this with a
>> variadic argument.
>>> 
>>> 
>>> I am a little confused- isn't linear gamma '1.0'?...   Or is this saying
>> that it is converting everything to 1.0 internally for calculations and
>> then back to work properly with 2.2 screen gamma in GL Viewport and Render
>> View?
>>> 
>>> So should I leave my Render View at 2.2?  It seemed to look better at
>> 1.0 for my PBR renders...
>>> 
>>> Thanks,
>>> Craig
>>> 
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>> 
>> 
>> 
>> --
>> Cheers,
>> 
>> Peter B
>> 
>> --No, I am not on Facebook.
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>> 
> 
> 
> 
> -- 
> .................................
> //sim+light+render
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