Open Last VFB Does Not Include Post Process Layers

[OPEN_RANGE]

If i open a project that I have previously rendered and then I click to render the scene, the VFB launches and renders the scene using all the Layers like Filmic Tonemap, Exposure, White balance, Lens Effects, Light Mix, De-Noiser and their corresponding settings previously used. IOW - I had the scene and all the render setting layers the way I wanted. I save and close Max. Then when I re-open the scene, and render again all those settings are in place just as before. That is great.

I have found the if I instead use "show last frame buffer" and then load a previously rendered .exr. into the VFB, then none of the Layers like Filmic Tonemap, Exposure, White balance, Lens Effects, Light Mix, De-Noiser and their corresponding settings previously used are loaded.

I'm not sure if this is something that could or should be corrected? I found this out because I needed to render a small part of a previously rendered .EXR file. I loaded it into the VFB so I could use region render to render the small part that needed changing, versus rendering the entire image again. Problem was as described above - none of the post layers were included.

[vladimir_krastev]

Hi the layer structure is lost if you open an image in the VFB. If you want to load a vrimg or exr to edit in the VFB you need to save your layer presets before that:

[vladimir_krastev]

One more thing. There is a check box called "Auto Load Layer". If you enable it and are using exr or vrimg file formats the layers/corrections will load together with the images.

[OPEN_RANGE]

Hi Vladimir,

Thank you for your reply. I looked at my VFB settings and the History and Auto Load Layer were both checked (by default i think). Still if I then open a previously rendered .exr it does not open with the layers. Also, finding that if I open my scene in 3DS Max and click render, the VFB starts up and has all the layers with their settings in place. If I then use load image to load a previous rendered .exr then the layers are not included. If I clear the image from the VFB and close the VFB, and then click render again, the layers are no longer included.

I am not sure what the "Auto Load Layers" setting really does? Loads layers but maybe only for for an image that has been saved to the VFB history?

Possibly there are reasons for why this cannot be done but imo, it would be a nice little improvement if the layers were not lost when using load image to load a previous render into the VFB.

Thanks again!

[yavor.rubenov]

Hello,

There are couple more things to exrs and automatic loading layers.
- The setting is in the History option but it affects all image loading (historically it was there..). So if you turn it off - it will affect loading from the File menu too.
- We save Layers only to exrs or vrimg files. Other formats (like jpg/png) don't have the layers.
- We can only save Layers to exrs/vrimgs written through V-Ray's own output. The output in Render Setup -> Common tab is written by 3ds Max so exrs saved from there won't have Layers saved.
- When saving those layers to exrs/vrimgs we also write a flag - are the color corrections baked into the RGB channel. For example if you save an exr from the VFB File menu -> "Save all image channels to single file" - we create an exr file with corrections baked in. We also save the layers as metadata and the flag that corrections are baked in.
- When loading images into the frame buffer we check if the image has corrections baked in (using the mentioned flag). If corrections are baked in - we do not load layers as loading them will cause double correction.

So in short
- if you want to keep the layers that come with the Max scene - turn the "Auto load layers" option OFF.
- if you want to load layers from external images - have the "Auto load layers" option ON and check how you save those images.

Best regards,
Yavor

[OPEN_RANGE]

Thank you Yavor. that is all very helpful info and explanation.

Am I correct in saying that, for the purposes of this discussion, "Layers" always refers to "Correction Layers" (versus layers generated by render elements)?

My current workflow is to render an EXR with Correction Layers and then click "Save Current Channel" button from the VFB. Current Channel is RGB. (I do not currently use Layer compositing in post processing). Typical final image size is 3800px x 2534px (3x2). See attached screen grab.

I open the EXR in photoshop and typically flatten to 16 bit, save as smart object then use a bit of camera raw filter, add my logo, minor touch up with clone tool if needed, etc. Flatten image and deliver as JPG and PDF to client.

If I need to go back and render some small area to accommodate client request or fix something it's nice to be able to use render region and only render what's needed versus rendering entire image. For that I load the saved EXR into the VFB. I want to render the region and include all of the original "Correction Layers" settings so the render region matches the original.

I am experimenting with various combinations of saving the Correction Layer Tree preset and turning off "Auto Load Layers", and then loading a saved EXR into the VFB. I am unfortunately now more confused then I was before. Can you suggest how I might best accomplish rendering a small region of a previously rendered EXR and retaining the same "Correction Layer" settings as used in the previously saved EXR? Also need to avoid the potential "double correction" you point out.



Thanks for any help and please forgive my limited understanding of how this all works.

[yavor.rubenov]

Yep Layers here refers to correction layers - the ones in the VFB Layers tab.


With "Save Current Channel" - you get an exr that has no VFB layers (color correction settings) saved inside.
If you load such image and the "Auto Load Layers" option is ON - loading will overwrite your current color corrections with defaults. You probably don't want that.

If you load such image from the File menu and the "Auto Load Layers" option is OFF - loading will keep your current scene color corrections. If I understand correctly - this is what you want.
You can now select your render region and render. You get the needed changes in the region.

But there's another issue - you loaded the image with VFB corrections baked in. The rendered region will have the VFB corrections but the rest will have VFB corrections twice.

You said you are adding some more corrections in Photoshop (camera raw filter etc..) - then the rendered region will not contain those changes and the result inside the region will differ ?
As a workaround you could load the original exr in the VFB, tune the region you want and before the final rendering - clear the image in the VFB. You can do the final render in the region only, apply the VFB corrections and save the image. Then in Photoshop you can compose it over the original one and do the additional color corrections there ?

[OPEN_RANGE]

I am experimenting with this and coming up with somewhat different results then you describe. Not sure where I am going wrong.

I understand the with "save current Channel" the color corrections settings are "baked in" and no VFB or Render element layers are saved as separate channels/layers. That is what I do and what I think I want. I have no need to make use of the separate channels for my simple work flow.

When I load such and image into the VFB with "Auto Load Layers" ON, it looks as it should. No overide or overwrite or other change has occurred. BUT, all the Correction Layers I had originally rendered it with are gone and, as you say, have been replaced by the default , which is no correction layers.

If I set "Auto Load Layers" OFF, then clear the image form the VFB and close the VFB, then use open last VFB to open the blank VFB and use File>Load image to load the EXR, I get the same result as above. The image looks as it should but all of the layer corrections I had in place are not there.

I see no difference between loading the image with Auto Load Layers On or Off.

If I have saved the Corrections Layer tree, and I load those saved corrections in the VFB and then Ioad the EXR into the VFB with "Auto Load Layers" ON, the saved/loaded Corrections Layer Tree is removed and replaced by the default (no correction layers).

If I have saved the Corrections Layer tree, and I load those saved corrections in the VFB and then Ioad the EXR into the VFB with "Auto Load Layers" OFF, the saved/loaded Corrections Layer Tree is retained but now the image is double corrected and not usable.

I think I need to do what you are describing above as a workaround, but I don't view it as a workaround. I view it as the only way to go back and render a region with the same Correction Layers as originally used. To accomplish that one must save the Corrections Layer Tree as a preset, so it can be loaded again when rendering a region.

[yavor.rubenov]

If I set "Auto Load Layers" OFF, then clear the image form the VFB and close the VFB, then use open last VFB to open the blank VFB and use File>Load image to load the EXR, I get the same result as above. The image looks as it should but all of the layer corrections I had in place are not there.

Are you resetting the scene or loading some other Max scene ?

[OPEN_RANGE]

Thank you for your ongoing help Yavor. I am not resetting the scene or loading another max scene. I am clearing the image from the VFB and closing the VFB and then loading the image into VFB.

[yavor.rubenov]

I'm trying to reproduce what you are describing but if I have Auto Load Layers" OFF - the VFB layers remain as they were before loading.

Can you record a video of what you are getting ?

[OPEN_RANGE]

I'm going through the steps now. Sorry I don't have a utility to record a video of my screen and steps I'm taking.

Sequence A:
1) Start Max>Open Scene>Choose Show last Frame Buffer to open frame buffer.
2) VFB opens with no image and the correction layers that I have set up are shown.
3) Checking VFB History settings and Auto Load Layers is OFF/unchecked.
4) Load previous rendered EXR and the image appears to be double corrected and if I turn off the correction layers it appears as it should.

Sequence B:
1) Set VFB History settings Auto Load Layers to ON.
2) From VFB >Clear Image
3) Load same EXR as before
4) Image loads without any of the correction layers I had set up.
5) Load saved Corrections Tree> Image goes away and is replaced by gray bands.
6) Load same EXR as before and Image loads without any of the correction layers I had set up.

I'm thinking this is all the expected results and I need to use the "workaround" as you describe to effectively render a region with the correction layers and then paste that into the image in my final photoshop file. That is not really a problem to do, but it seems it is the only way to accomplish this type of render region, small area fine tuning.

I wasn't aware of and then not understanding the Auto Load Layers option. You have provided me with a much better understanding of this. Thank you for your help!

[yavor.rubenov]

The B.5 part is interesting and shouldn't happen Can you send us one image and one saved corrections tree that demonstrate the issue ?

I wasn't aware of and then not understanding the Auto Load Layers option. You have provided me with a much better understanding of this. Thank you for your help!

Welcome

[OPEN_RANGE]

OK. I think I need to send you link to dropbox or google drive where you can downlosdit. Who/where should I email a link too?

[yavor.rubenov]

You can post it here if it is not confidential or send it to our support.