instant colormapping?

[percydaman]

My understanding is that you dont have to recalculate a saved irradiance map if you adjust color mapping features. So why must we rerender the image if we adjust colormapping? why not have colormapping controls as part of the vray vfb? or is it already enabled somehow?

[Dynedain]

I agree

[travistlo]

if im not mistaken isnt that one of the things listed in that huge post from Tom?

If it isnt, that is a great idea.

[Dynedain]

frankly a lot of that huge post of tom's went right over my head

[samuel_bubat]

Alternatively you can use a compositing software for adjusting color mapping/exposure.
I´m using Digital Fusion and it just works great !
You need to render your image in linear mode, activate unclamped
colors and save as RPF or HDR (32 bit per channel).
In the compositing app. you need the following color correction tools
in exactely that order to get the best results.

1. Color Gain.
(only if you have very bright scenes lit by a ies sun or similar)
to scale down your color to a good visible range.

2. Gamma
to brighten up dark areas.
Remeber those "my window region is to bright but my room is to dark"
posts. Gamma lets you adjust this very comfortable.

3. Saturation
Use a little saturation to reconstruct the colors wich where
washed out by the gamma correction.

4. Levels or curves
Use Levels for for finetuning and contrast adjustment.

check these images (made some time ago with another renderer )
http://sorceress.netfrag.org/optix/fusion_exp/

The first 3 images show a simple room lit with an ies sun.
without exposure, with max log. exposure. and one with
the technic described above.

The advantage: You can animate these settings quite easy
So imagine you have a camera flying from an indoor to an outdoor
scenery with photometric lighting. You can easily adjust
your lighting situation for a certain camera location.

The disadvantages.
You´ll need much more samples to avoid splotches in strong
corrected areas.
You cannot use adaptive antialising.
You´ll need to adjust the gain very carefully to prevent
aliasing on shadow edges.

So my idea for the vray framebuffer.
Make a standalone tool instead of an inbuild framebuffer
Wich can handle sequences as well and is able to animate
most important color parameters. Further It would be great to have
these features G-Buffer based as well !!

If your interrested in these technic and you don´t have Fusion
or something similar, you can use HDRShop in conjunction with Reinhard´s
ToneMapping plugin. It works but not very intuitive.
(Shame on Photoshop at this point wich is still not able handle 32bit per
channel images... pfff)

cheers...

[cpnichols]

I agree with Samuel... Compositing is really the only way to go. having to do a complete rerender... even if you do have the GI baked in, is a complete waste of time compared to the near realtime feedback of compositing. The fact that Vray can output the GI and direct light as a seperate pass gives the ultimate control. Then one can control the saturation, contrast, etc... The key, as Samuel said, is the floating point fileformat, such as HDR, or EXR

[percydaman]

sure, you have a point. But some people can't or dont feel the need to use compositors. Never hurts to give options to everyone.

[Nenad]

Never!

[percydaman]

/me whips out his oversized trout and starts waving it at Nenad....

[visions]

Has this been implemented?
Do i have to re-render a frame to adjust color mapping settings, even if i use the Vray FB?
I have been hunting for this the whole morning and couldnt find any definative answer.....
Tia
Vivek

[panthon]

I agree with Samuel... Compositing is really the only way to go. having to do a complete rerender... even if you do have the GI baked in, is a complete waste of time compared to the near realtime feedback of compositing. The fact that Vray can output the GI and direct light as a seperate pass gives the ultimate control. Then one can control the saturation, contrast, etc... The key, as Samuel said, is the floating point fileformat, such as HDR, or EXR

And if u add object id selection from gbuffers to the mix, u should be able to adjust only the gi for example in one single object, or the direct light, the reflection, whatever. Useful for that washed out objects that force u to adjust the overall levels, or simply to correct for that questionable wishes of our clients

It would be cool to have "object containers" which would give u the ability to change every single parameter of all objects in your scene in post.

SAmuel_BUBAT wrote:

The disadvantages.
You´ll need much more samples to avoid splotches in strong
corrected areas.
You cannot use adaptive antialising.
You´ll need to adjust the gain very carefully to prevent
aliasing on shadow edges.

Why can´t u use adaptive? I´ve noticed antialiasing problems when playing with gain values too, but particularly in bright areas. Is there a limit or something? Do u know why it is happening?

What do u do when u find that the difference in exposure between the bright areas near the windows and the dark areas deep into the room is too big? How can u adjust these situations without unbalancing them?