Material property values are colour managed Tweet

[QuinceHungaryKft]

The values for material setup are colour managed making it difficult to fine tune properties. For legacy compatibility I propose to implement a checkbox for disabling colour management on a value.

[calus]

The values for material setup are colour managed making it difficult to fine tune properties. For legacy compatibility I propose to implement a checkbox for disabling colour management on a value.

Not sure what you mean here,
as far as I know, values itself in Octane Material are not color managed, only the color swatch display is color managed by Maya,
in the color picker you can set color as you like, using display space or rendering space or without color management.

What am I missing ?

[QuinceHungaryKft]

I was referring to some of the basic material setup options such as specularity, roughness where the color picker isn't available.

A simple test of dialing in 0.5 values for any if these properties will not result in a 50% calculated value. If you compare specularity of .5 to 1 you'll only notice a small difference. The same goes to roughness maybe even more obviously.

My current workaround when these channels are not driven by maps is to connect it with a colorCorrectTexture node, set gamma to 2.2 and use the brightness as a driver. With this workaround, you'll immediately notice that the values behave more naturally (in a linear fashion).

note: We are still using v2 until our upgrade next week, so I'm not aware if this is still the case in v3.

[QuinceHungaryKft]

The values for material setup are colour managed making it difficult to fine tune properties. For legacy compatibility I propose to implement a checkbox for disabling colour management on a value.

Not sure what you mean here,
as far as I know, values itself in Octane Material are not color managed, only the color swatch display is color managed by Maya,
in the color picker you can set color as you like, using display space or rendering space or without color management.

maya_2017-01-01_14-53-30.png

maya_2017-01-01_14-52-03.png

What am I missing ?

Hi Calus,

Sorry for replying so late. Let me give you an example:
Set up a glossy material:
Check the roughness slider for instance. The effect increases rapidly and after a value of .5 there is basically no difference in output while at values 0.001 and 0.002 you can notice the difference. To fix this I'm using the following hack since a while:
I connect to these sliders a ColorCorrectTexture node, where I set the gamma to 2.2 and use the brightness slider to feed the desired input to roughness, specular etc. If you follow this, than you'll immediately notice that the material attributes will behave in a much more natural and expected way.

[calus]

Hi Calus,

Sorry for replying so late. Let me give you an example:
Set up a glossy material:
Check the roughness slider for instance. The effect increases rapidly and after a value of .5 there is basically no difference in output while at values 0.001 and 0.002 you can notice the difference. To fix this I'm using the following hack since a while:
I connect to these sliders a ColorCorrectTexture node, where I set the gamma to 2.2 and use the brightness slider to feed the desired input to roughness, specular etc. If you follow this, than you'll immediately notice that the material attributes will behave in a much more natural and expected way.

Here is my theorie :
These Octane attribute curves follow the underlying math,
but closer to physical is not not always easier to use,
the attribute values are the same in the plugin as in Standalone.

But as you said, we are used to something else in legacy renderers or with PBR shaders:
the attributes use a different curve, a trick, the attributes are squared to make them more handy to use, a more linear curve...
(So basicaly with your ColorCorrectTexture node and gamma 2.2 you are reproducing by coincidence almost the same trick: squaring the attribute, but this is not relative to color management)

Another way to deal with this is to make the cursor itself following a logarithmic progression, like in Standalone for some attributes, but not sure it's possible in Maya attribute editor.

Honestly as I'm working with unbiased renderer since a long time I'm used to these attribute curves, and they feel natural for me.
Nevertheless I agree squared attribute's curves would really be more handy to use,
Octane 3.1 will be able to support other shaders trough OSL,
and specially the industry standard AlShader, I think this one use Squared attribute curves.