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

Peter Bowmar pbowmar at gmail.com
Thu Nov 21 12:32:26 EST 2013


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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