I think I finaly get the LWF :D

[n6]

I m not sure that the gamma value are 100% correct since I m on a LCD monitor and doesnt have hardware calibration spider.
But after 30 reading of all the LWF post I think I get it :


This image was before anderstanding the LWF thing :






And this one is after :




If some expert could confirm it looks like a linear work, I would be pleased :d



EDIT#######################

Here is the same scene but with VRay Physical Camera

[powerandrubber]

I think you're getting it. See how oversaturated the first image is.

[DaForce]

That looks pretty good n6!!

What LWF method did you use?

[n6]

Well in the first image I have
-the VRaySun set to 0.1 and VRaySky to 0.05
-render the vrimg and extract from it the exr
-open the exr in Photoshop and set the gamma to 2.2 (what give me the same result as the VRay frame buffer)
-converted from 32bit to 8bits
-saved the image as jpg

In the second image :

-set the bitmap input gamma to 2 in MAX
-I have set the curve in the VRay FB like in the LWF tutorial
- with this display parameter I have been able to decrease the sun and sky multiplier values :
-the VRaySun set to 0.06 and VRaySky to 0.03
-render to vrimg and extract the exr
-open it in Photoshop
-convert it to 8bit
-saved it to jpg

[DaForce]

hey n6

For simplicity sake, use max gamma, and turn on gamma correct color mapping and use 1.0/0.45454
Then render to VFB and save as jpg.
All done. It saves some steps and because your using color mapping it helps get more samples into the darker areas.

Also if you have a build that has the VrayPhysicalCamera use that and then leave the sun and sky at 1.0 and play with the f-stop shutter and ISO to get a nice lite (make sure exposure is ticked)

[n6]

hey n6

For simplicity sake, use max gamma, and turn on gamma correct color mapping and use 1.0/0.45454
Then render to VFB and save as jpg.
All done. It saves some steps and because your using color mapping it helps get more samples into the darker areas.

Also if you have a build that has the VrayPhysicalCamera use that and then leave the sun and sky at 1.0 and play with the f-stop shutter and ISO to get a nice lite (make sure exposure is ticked)

yep I get this methode too, but I prefer to go with 32bits hdr till this end.

The physical camera is realy great but since my main goal is texture baking I cant tweak my renders with it in the process since the correction it applies to the image would not be present on the baked lightmap.

But I think that physical camera is physicaly correct while the standard one isnt.

Also some questions come with a Vlado post on the physical camera :
He is talking about ISO as a parameter for the physical camera. I anderstand the ISO sensibility but in the version I have, no parameter is called "ISO". Is it in a new version? I have the 1.49.34

[DaForce]

Ah yes, well if your texture baking then the i would advise against the Vraycamera .. good point.

Yeah there is a newer version.
Hmm maybe its not called ISO maybe something else? default is 200 ( i think)
In mine its the very last option.

[Candelero]

There is an ISO parameter in the final version of the VRay Camera.
It acts exactly as ISO of a film.

Best regards,
nikki Candelero

[n6]

I have updated my first post with an other shot from a Vray Physical Camera and LWF but without any ISO parameter

[ene.xis]

All done. It saves some steps and because your using color mapping it helps get more samples into the darker areas.

i thought so too...

This also means that in 2 and 3, the image isn't gamma corrected at rendertime (it is done in the viewing system: throb curve, max display gamma, PS color profile). So it is in fact a pretty dark image. Vray will sample dark areas not so good, resulting in bad AA for example.

Yes, BUT, your monitor (if calibrated correctly) will darken those areas again later on, so the bad AA will not be visible. In that case, it will be a waste of render time to make V-Ray take more samples when they will not be apparent.

Best regards,
Vlado

[DaForce]

Looking good n6!!
Now try to get an exterior render working with LWF

ene.xis:
Yeah it sitll does put more samples in the darker areas tho, weither you see them or not doesnt matter. And even if the area is still dark i still reckon you would see the AA issues. IMO