6 replies to this topic

[Just_Asking]

Hello,

I am used to render everything in 1.8 gamma for my display device. I hoped that mantra renders everything in linear space [there's such information on sidefx.com] - even colors in materials, lights etc.
After my few tests I see every color is rendered in gamma corrected space [2.2]. Maybe I am something missing... anyone knows what's going on?

Edited by Just_Asking, 09 August 2012 - 11:54 AM.

[CeeGee]

Chk this tutorial

https://vimeo.com/42486306

[symek]

Just_Asking, on 09 August 2012 - 11:49 AM, said:

Hello,

I am used to render everything in 1.8 gamma for my display device. I hoped that mantra renders everything in linear space [there's such information on sidefx.com] - even colors in materials, lights etc.
After my few tests I see every color is rendered in gamma corrected space [2.2]. Maybe I am something missing... anyone knows what's going on?

Mantra definitely renders in linear space.
Mantra doesn't linearize textures automatically. sRGB textures have to be converted or corrected by a shader.
Mplay/IPR display renders linearly unless instructed differently (via gamma or lut menu).

You could provide a test scene with i you have any doubts.

[Just_Asking]

SYmek, on 09 August 2012 - 01:40 PM, said:

Mantra definitely renders in linear space.
Mantra doesn't linearize textures automatically. sRGB textures have to be converted or corrected by a shader.
Mplay/IPR display renders linearly unless instructed differently (via gamma or lut menu).

You could provide a test scene with i you have any doubts.

I really know that most textures are in SRGB space and you have to remove the correction by your own.

The problem is color swatch - it's not texture, it's just an input and it seems to be in 2.2 gamma space. If you do not believe me just go ahead and create scene with grid and constant shader on it. Then render - it will be the same color for render and for shader. When you will correct it in mplay or whatever to 2.2 gamma you will have 2 diffrent colors - desaturated for render and correct one for shader.


I am sure that Houdini works in full linear space, I just want to know why color swatches are desaturated after gamma correction, and the textures [those in linear space] are correct.



By the way, 3ds max, maya and XSI have also the same issue, but mray and vray have option which stand for "color swatches to linear". Before that "feature" you had to use some scripts or just do it by your own using gamma tool/node on every single constant color.

Edited by Just_Asking, 09 August 2012 - 02:17 PM.

[edward]

By default, there is no color correction in the color swatches. You can change this (eg. set it to gamma 2.2 to match your monitor) in the color preferences.

[symek]

Just_Asking, on 09 August 2012 - 01:58 PM, said:

The problem is color swatch - it's not texture, it's just an input and it seems to be in 2.2 gamma space. If you do not believe me just go ahead and create scene with grid and constant shader on it. Then render - it will be the same color for render and for shader. When you will correct it in mplay or whatever to 2.2 gamma you will have 2 diffrent colors - desaturated for render and correct one for shader.

Checkout Color Correction section then:
http://www.sidefx.co...f/windows/color

[Just_Asking]

Thank for help!

Houdini amazes me every single day

Edited by Just_Asking, 10 August 2012 - 09:21 AM.