Author Topic: HDRI Gamma problem  (Read 1578 times)

2019-06-26, 13:26:45

Nube architetture

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hey everybody, how are you ?

I have a little problem

I can't use properly peter guthrie skies.
Usually i use a corona light material with an Hdri map, in the same panel i change the exposure of the map to -4.3. Then i apply a filter to correct the gamma to 1 to 0.75 (Just for boost the shadows)  but the result is very ugly. The problem is the oversaturated colors, the sky is too cyan. 

could  anyone help me ?

What is the right way ? Are there any tutorials that could help me ?

I prefer don't use the combination with hdri and corona sun, i'm looking for a method to change the gamma but not the color.

Thanks guys

2019-06-26, 14:11:27
Reply #1

burnin

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You can use Cinema's Filter Shader on any HDRI, texture, ... within Corona Materials.

2019-06-26, 21:40:44
Reply #2

Nube architetture

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i've tried to render the same image on 3ds and c4d.
With the same parameters, same HDRI, same exposure and gamma.

The c4d image has more cyan and blu in the shadow and the sky is oversaturated and more close the cyan, the image looks unnatural.

The 3ds version has a very soft shadings in the sky more close to the blu, the light looks more naturale and i like it.

Both images has the same parameters. Both used a bitmap with a corona color correction, c4d image has a c4d filter to change the gamma (this is the only difference) .

Anyone knows how can i reach the same result on c4d ?

I don't know if it is the right section to post something like that.

thanks bye

2019-06-26, 22:28:12
Reply #3

burnin

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from the looks it feels like you're not working the same linear workflow - something's a miss

2019-06-27, 10:28:37
Reply #4

Nube architetture

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This is the informations that i found

C4d has the tick on the linear workflow option.



2019-06-27, 11:50:37
Reply #5

Nejc Kilar

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Interesting stuff... Have you perhaps try double checking if the bitmap is imported with a linear profile? Also, is there a huge difference with the "filter" being applied or just the bitmap on its own?

2019-06-27, 12:26:08
Reply #6

Nube architetture

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This is the material that i have applied to the sky

2019-07-01, 17:57:28
Reply #7

Nube architetture

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hey guys
One week after same problem
could anyone help me ?
I'm really struggle with it  :(

thanks Bye

2019-07-01, 20:57:55
Reply #8

Ales

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Hi,

to summarize, in 3ds Max you have bitmap with input gamma set to 0.76, this bitmap is then modified via color correct (reducing exposure) and used for environment and you want to recreate this setup in C4D? In that case there are two things you need to change:

  • input gamma that you specify when opening bitmap in 3ds Max (and that can also be specified in C4D when using Corona Bitmap) is different from gamma in C4D filter shader - input gamma means gamma that image is expected to be saved with while gamma in filter shader is gamma you want bitmap to change to. So in filter shader you need to use value 1.32 (i.e. 1/0.76).
  • you probably want to apply gamma first before changing exposure, so you need to swap Color Correct shader and C4D filter shader

Apart from these, you might also want to check you use the same tone mapping settings in both 3ds and C4D.