Multichannel EXR: Corrections are not saved to render elements

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

Hey guys,
I found another issue with Multichannel EXR that is driving me nuts. In the VFB, we apply several corrections to the image, like exposure, white balance etc to get a better match to the reference plate.
When saving the EXR as seperate channels, those corrections are saved to the render elements as well.
When saving to Multichannel EXR, the corrections are only applied to the RGB, the render elements are saved without corrections.

Please find attached to screenshots.

Left side, RGB element from seperate EXR, right side RGB from Multichannel EXR. Both look identical.

rgb.jpg
rgb.jpg997×501 117 KB

Left side, lighting element from seperate EXR, right side lighting from Multichannel EXR. Right side is missing the corrections made in the VFB.

lighting.jpg
lighting.jpg997×502 75.3 KB

So, how can this discrepancy be avoided? Of course, the checkbox to save the corrections are set for both ways to save, please see settings here.

settings_01.jpg

settings_02.jpg
settings_02.jpg263×125 9.42 KB

2

Well, the options’ names are such for a reason. You could export the Color Corrections as a .LUT (VFB > RMB on the Display Correction layer > Save All CC to LUT) and apply it later.

3

Which is useless in Photoshop.
There’s no other way to bake in the corrections, just like the seperate channels option?

4

What do you mean? PS has a Color Lookup layer adjustment that acceps .cube files.

Not that I know of.

5

Yes, but it will look different.

6

if you are careful about what gets saved to a LUT from VFB it can work between VRay and Photoshop. not all the adjustment layers are saved to lut. all you get is a very simple 0-1 range cube lut.

your options are Reinhard compression or some kind of log encoding (log would be custom curves in VFB and .csp lut is PS) before other VFB colour corrections (that would be saved to a lut).

edit:
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7

making custom curve adjustment:
when you save .vfbl file from VFB with curves adjustment layer included, you can edit the points. you can make points linear first, input just “point centre” and than smooth it automatically.
looks like this:

“class”: “chaos.cc.curves”,
“properties”: {
“version”: 1,
“name”: “mP_AgX_KrakenLog”,
“enable”: true,
“expand”: false,
“expandable”: true,
“blend_mode”: 0,
“opacity”: 1.0,
“show_preview”: true,
“curve_graph”: {
“version”: 1,
“Master”: {
“points”: [{
“point_type”: 0,
“point_center”: [0.0001347560901194811, 0.0000720880925655365]
}, {
“point_type”: 3,
“point_center”: [0.00029164133593440056, 0.044006794691085818],
“left_vector”: [-0.00005229508315096609, -0.014576690271496773],
“right_vector”: [0.00002810347177728545, 0.007833539508283139]
}, {
“point_type”: 3,
“point_center”: [0.0003759517567232251, 0.06674453616142273],
“left_vector”: [-0.000028103473596274854, -0.007100209128111601],
“right_vector”: [0.0001734105171635747, 0.04381134361028671]
}, {
“point_type”: 3,
“point_center”: [0.0008961833082139492, 0.1424470841884613],
“left_vector”: [-0.0001734105171635747, -0.014875858090817929],
“right_vector”: [0.00047536217607557774, 0.040778495371341708]
}, {
“point_type”: 3,
“point_center”: [0.0023222698364406826, 0.22634030878543855],
“left_vector”: [-0.00047536217607557774, -0.018413471058011056],
“right_vector”: [0.00047443489893339574, 0.018377553671598436]​…​