VFB , Saved composite layers : how does it work?

[francomanko]

I'm a little confused on how the VFB is remembering composite setup and previously saved setups from other images.

The issue i just had again, is that I have a new scene, in a completely different project, and I've made a setup based on an IPR render of the scene. Then i do a production render and the composite setup has loaded a completely different one, from an image on a different project.

So where and how is the VFB saving/using the data? Is there any info on this?

I know the screenshot isnt the best example, but clearly you can see the composite setup is from a different image, and none of the saved images in the history have that setup either. (I have a sneaky suspicion that something isnt right, and it could well be to do with lightmix...but not sure as yet.)

[vladimir_krastev]

Hi, thanks for posting. The VFB layers can be stored in the exr/vrimg or saved trough the "save layer tree preset" button.

From the docs page about VFB layers:

Layers are only saved to .exr and .vrimg files written through V-Ray's own output. The output in Render Setup > Common tab is written by 3ds Max so .exr files saved from there do not have Layers saved.

When saving layers to an exr/vrimg file, V-Ray writes a flag indicating whether the color corrections are baked in the RGB channel. For example, if you save an exr from the VFB File menu > Save all image channels to single file option, V-Ray creates an .exr file with corrections baked in. It also saves the layers as metadata and the flag that corrections are baked in. When loading images into the Frame Buffer, V-Ray checks if the image has corrections baked (using the flag), and if such are found, the layers are not loaded because this causes double correction.

If you want to keep the layers that come with the Max scene, turn the Auto Load Layers option off from VFB > Options > History tab. If you want to load layers from an external image, enable the Auto Load Layers option and check how you save those images.

[francomanko]

thanks for the reply, sorry i think i didnt explain myself well enough as its a bit odd But i wasnt really meaning the explanation you posted which i understand, i think it was more, that something is acting a bit strange, because as i mentioned in the post, this was a fresh render, yet it came in with layers saved from a different image in a different project, no saved exr or anything...so i was wondering what was going on and how it came to load these layers? You can see from the screenshot, the comp layers were for a shot containing wall and floor tiles etc, completely different from images in the saved history and the render itself.

[francomanko]

Whilst i was trying to see what im doing wrong I noticed that if I load a renderpreset, where the only saved settings are 'VrayGPU' and not 'Effects,Environment or Render Elements' it resets the previous lightmix settings, is this intended because its not ideal, especially when you are using previously saved composite settings etc.