multichannel exr from vfb smaller?

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

i set my multichannel exr to save via “save vray raw image” i also tick “32 bit output”

i get a 700 meg exr

same scene, i use the “save all channels to a single image” option in vfb to save an exr. There are no options for the exr available.

exr saved is 350 meg.

what gives? is it only saving a 16 bit exr?

2

The RAW one use’s vray settings to save, where the other one uses max’s settings.
Also, when setting the raw one’s path and filename, at the very bottom of that window are additional options.

Besides that, you can adjust the settings for VRay’s raw version, by checking the options in the renderelement: VRayOptionRE

3

So when i save a multichannel exr from the vfb, and no options are presented before it saves the exr, how do i adjust the settings?

4

nobody? seems very odd that a) saving a single exr from vfb presents exr options, b) saving vray raw exr has options, saving multichannel exr from vfb has no options, and is half the size of a “raw” exr

5

if you don’t tick 32bit output in the 1st instance when saving RAW, then the file should be similar size
that results in a 32bit, half float (16bits per channel) image

The fact that you cant click 32bit output in the multichannel save directly from vfb, might be done on purpose, or perhaps just an oversight from the devs. guess we’ll have to wait for them to respond to find out which

6

Exrs saved directly from the VFB are saved as 16-bit purposefully. What’s the necessity to save as 32-bit? Is there information missing?

7

Quite simply our compositor wants 32 bit files.

ive saved a load of images and revisions out, some via raw and some via vfb, assuming it was basically the same thing, since both save a multichannel exr. I also assumed they shared setttings in some way.

ive now been asked why some files are half the size of others, and obviously there is a risk that swapping a 32 bit file for a 16 bit one in a 32 bit comp with a rebuilt beauty pass, might produce different results, which is entirely unacceptable.

now i know (is it documented anywhere?) , i will have to avoid this option. , however i prefer to save from the vfb unless im network rendering, since the raw file save has the annoying habit (feature) of saving a huge multichannel file, even if you cancel the render 1% complete. this wastes time (sometimes minutes) and hard drive space.

i dont understand why you would purposefully limit the vfb multichannel exr export to 16 bit instead of having a tickbox, like the raw save option..? whats the logic?

8

We don’t have an option to force 32-bit files from the VFB; color channels will be saved as 16-bit, whereas other channels (Z-depth, world position) will be saved as 32-bit. We will see if we can add an option for this in the future.

Best regards,
Vlado