LWF and new colour mapping 1.5

V-Ray V-Ray for 3ds Max General
1

So finally finally finally started to get my head around using LWF (linear work flow)

We just upgraded to v 1.5 and the colour mapping options have changed so I just want to be sure of what workflow is correct with 1.5

Running max 9 so going to customize/ preference/ gamma lut
and
changing gamma to 2.2
checking affect material and colour selector
and under bitmap files changing input gamma to 2.2

We render to 8-bit tga not .exr and so want to burn the gamma into the image rather than using throb’s curve in the v-ray frame buffer.

Before we used the gamma correction colour mapping with
bright multiplier at 1 and dark at .454
but in vray 1.5 the names have been changed to
multiplier-is this bright multiplier? and should it be set to 1?
inverse gamma-is this dark multiplier?and should it be .454

and a new option gamma which should be left at default or not?

2

Your first part sounds right, thats what I do. For stills I use .exr, but for animations I use .tga. What I do to “burn” the gamma into the TGAs is in the save dialog, under the Gamma settings, I click the Override radio button and specify 2.2. This makes them appear correct when imported in Premiere or AfterEffects as an animation sequence.

I don’t know about the last part of your question. With LWF I keep linear mapping at default unless certain areas are overbright or burnt out, in which case I switch to Reinhard and add some burn, usually about 0.5.

3

Sorry to butt-in…

@ Clifton - are you using LCD monitors, and if so are they calibrated to 2.2 or 1.0 as Vlado’s post back thru the mists of time?

Thanks.

4

I’m using LCDs calibrated with Spyder Pro to Gamma 2.2 and Kelvin 6500.

5

Thanks very much, have a Spyder express on order and needed to know which calibration to use.

Thanks again.

6

Hey Clifton Santiago
Thanks for the reply
I have some animations coming up and will try default linear mapping instead of using the gamma correction.

I haven’t used Reinhard at all but will look into it.

Its annoying that I had just got my head around how to do this with bright multiplier at 1 and dark at .454 went and changed the colour mapping panel

7

If you used gamma color mapping 1/0.455 in older version, you should now use linear 1/1 and set the gamma option to 2.2.

Then you’ll have the same, and if for any reason you would like another mode than linear, you have the option. (this wasn’t possible before as there was not the gamma option).

You can also leave gamma=1.0 and instead of using throbs curve, use the srgb button. But note that this has an effect on qmc sampling since it is sampling on a darker image than the one you are looking at.

Consider trying exr, with floating point option selected. Then you can under or overexpose your image in photoshop instead of having to rerender the scene (your above white data is not clipped out). Exr is like hdri, and it’s awesome!

8

Hi Flipside,

I understand that Gamma Correction 1/0.454 (in older version) is now replaced with Gamma 2.2 (in 1.5 version) and independent to whatever Color Mapping type we chose.
This is clear enough so far … pretty simple and direct.

Now, question is:
What is the purpose of Gamma Correction item now? I notice that we still have Gamma Correction item in the drop-down list.

9

I guess it’s there for backward compatibility.

10

Exactly as Flipside said. I also second his comments on using exr. That’s all I use now. Worse-case scenario (for like a client let’s say), I just batch format conversions in Photoshop.

You can also do 1/.45454 over 1.0 gamma and that will burn in and should give the same exact results although you lose the brightening/darkening controls.