LUT Setup export for Vray Frame Buffer Color Correction

[Dynedain]

How difficult would it be to be able to export the vraybuffer curves correction to an LUT Setup file (I noticed bezier curves is one option already) so that it could be imported into a compositor? (Do other compositors besides combustion have this ability?) I'd really like the idea of being able to setup the color correction in VFB, and then be able to use the same correction in Combustion while maintaining a linear file. I dont really like guestimating to make the curves look the same.

[panthon]

Hi!

I would be very interested in knowing about that too... but I can´t find a format to export from max to combustion retaining the image dynamic range...have u found any? I`ve been testing EXR with no luck...

I have tested HDR too, but combustion can´t import it...

[Dynedain]

I've since heard that 3DSMax can't natively save floating-point images..... but that vlado & co are trying to find workarounds

[panthon]

Excellent!

I find it quite frustrating when i´m able to review all that dynamic range on the vray VFB but it CAN´T be used in postproduction, whichever the program u choose... However, when u import an EXR into combustion, it detects the image as 128 bit, but the great range u get in max can´t be recovered in comb...

So, if it´s a problem from 3dsmax itself, do u think it will be solved with the arrival of 3dsmax 8? It´s supposed to export exr natively.

From the 3dsmax 8 tech specs:

-Enjoy more flexibility and dynamic range for lighting
adjustments post-render using the OPEN EXR rich file format.

There´s even a video demostrating the above:

http://download.autodesk.com/media/3..._max8_350k.wmv

Will it be compatible with VRAY? Im fed up with that "mental ray compatible" thingy

[panthon]

Well, it seems max 8 lets u export the EXR file using vray as the renderer, and it SEEMS to be imported correctly by combustion and photoshop. I´m currently testing if an extremely overexposed image can be recovered...That´s to say if u are able to use the full dynamic range in post.

My aim was to get similar results in post as u can get manipulating the curve color correction in vray framebuffer. It does seem it´s working but im not really sure about what kind of operator should be used in combustion so that u can take profit of the new vast image range u are getting...Currently i´m using the LUT support to tweak the parameters but im really confused about the workflow....

In theory, if u used EXR files combined with RPF buffers extracted from a second RPF file, u could get the best of two methods...HDR and Gbuffer postproduction methods...

If someone tries this out just let me now....it would be great if we could tweak an image beyond what was possible with a LDR image...no more rerenders for overexposed or underexposed images? Get ready picky clients

[Dynedain]

Once I get Max8 installed and running, I'll test it out. When i had been messing around with things, I had just been using the LUT controls on the imported footage node in Combustion. If your footage is set to be floating point in Combustion, you probably can work with it as a color correction modifier instead, but I don't know enough about it to verify.

Still, I too look forward to the day where I can quickly adjust/fix in Combustion instead of rerendering everything.

[panthon]

If your footage is set to be floating point in Combustion, you probably can work with it as a color correction modifier instead, but I don't know enough about it to verify.

Yeah, that seems to be the point. U can adjust levels this way, but i´ve tried the same thing without using a float point image, a jpg, and ive got similar results...I mean, i render an image with very dark shadows, i save it to JPEG, import it into combustion, activate LUT editor and change some settings and the result is almost identical to the openEXR equivalent...You can recover detail from these dark areas easily.

I´m confused and thinking something is wrong in the workflow. However im going to test it more extensively

By the way, a LUT parameters export would be cool as u pointed in your first post in this thread. However, I´m not sure if these thoughts belong to wishlist section

[rpc212]

Yeah, LUT export with the rendered image would be great! Would really help with compositing!