Vray VFB with standard renderelements

[KiboOst]

Hi,

Seems that for having deep data into our EXR, we need to use Vray VFB. (3dsmax 2014, Vray3.07).
We rarely used it because of render elements storing severe limitations, so back there ...

The problem is :
- We need exr with Zdepth deep data inside, and only this.
- We need all render elements saved like usual with max, separately, different formats, different folders, etc
- Having the beauty pass only in the exr and the deep data in another file would even be better.

Actually even if I check "separate render channels", the channels are still inside the exr !
Add a multimatte element in REs, render separate, load the exr into nuke and shuffle it, the multimatte is there also.
We don't want to generate huge exr with all passes inside (some are finally not used, some will change, etc so why dragging all this in the exr from start...)

So, either we don't understand Vray VFB correctly, or these are real limitations for workflow.
Any ideas or clarifications ?

[vlado]

There is no way to do what you want right now. You can render the deep pass separately, but the deep exr will still contain the RGB element. Note that it makes no sense at all to store z-depth element by itself into a deep exr file - the deep points carry the z-depth information anyways (plus mandatory alpha information).

Best regards,
Vlado

[KiboOst]

There is no way to do what you want right now. You can render the deep pass separately, but the deep exr will still contain the RGB element.

So the "separate render channel" is totally useless. Why would I need an exr with all elements inside AND all elements separately ? Why not having an option to store only beauty+deep into the exr and all other elements really separately ?
Actually this is a real breakpoint in our workflow causing lot of headaches. Only solution would be to render as usual without vray vfb and send another job with just vrayvfb for exr+deep !!

And even with a real separates elements option, why can't I save element x in png 24 and element y in exr rgba ??
Vray is so much advanced and open, seeing so much limitations for saving our renders is really surprising. No bashing here, sincerely, I just need Vray being even better and more flexible.

Vlado, is there at least a hidden way, via maxscript or python to remove all datas for the exr apart beauty+deep ?

Note that it makes no sense at all to store z-depth element by itself into a deep exr file - the deep points carry the z-depth information anyways (plus mandatory alpha information).

Yes sure of course.

[vlado]

Vlado, is there at least a hidden way, via maxscript or python to remove all datas for the exr apart beauty+deep?

No. But OpenEXR 2 is open-source, it is relatively straightforward for anyone to write a tool that would extract the channels that you want as separate files in any format you wish and leave only the deep channels that you need in the deep file.

Best regards,
Vlado

[vlado]

And even with a real separates elements option, why can't I save element x in png 24 and element y in exr rgba ??

<shrug> Because it was not done in the beginning and now it's a lot of code to change that would break a lot of things. It can be done, but I would need a serious reason for it.

Best regards,
Vlado

[KiboOst]

Vlado, I just spend 10k$ on Vray licences to update to v3. Is it a serious enough reason ?

I will try to write a python script to delete all but deep data in the exr, as post-render script. But not sur there is actually a python module reading deep channel (supporing exr2).

I just did a test where exr file with deep and five REs is 42Mo !! Same file stored with max vfb, without deep data, make 6Mo (sum of all files). Multimatte are 8bit rgb (no need for 16bit rgba in the exr for that, etc). This means 1Go per second instead of 150Mo. And we usually render with more render element than that ...

So, having exr deep only and separate mattes is really a must have...
Talking about that with with a few fellow, it seems a lot don't use vray vfb due to these limitations. And having to use to get deep will make these limitations a real problem for a lot.

[vlado]

Vlado, I just spend 10k$ on Vray licences to update to v3. Is it a serious enough reason ?

Hehe, when you put it like this, yes. But it won't happen overnight - like I said it's a lot of code that needs to be changed, and there will be lots of bugs along the way.

I will try to write a python script to delete all but deep data in the exr, as post-render script. But not sur there is actually a python module reading deep channel (supporing exr2).

I think there is, but I'm not sure either.

So, having exr deep only and separate mattes is really a must have...

But the whole point of the deep file is that you don't need the separate mattes!? You can extract any individual object perfectly.

Best regards,
Vlado

[KiboOst]

1) If you need special alpha/beta testing for this, we can help you (we are ever for many companies).

2) I can read the file with python 2.7 and openEXR 1.2.0 module. It show all channels (REs are indeed half, generating lot of datas for nothing) and I guess deep data are :
- Z FLOAT (1, 1)
- ZBack FLOAT (1, 1)

So I would have to keep these two, and RGBA:
A HALF (1, 1)
B HALF (1, 1)
G HALF (1, 1)
R HALF (1, 1)

I will script a test, delete all but these, and see if I can rewrite the exr and import it correctly with all deep data in compositing package. But even if it works it would only be a cumbersome workaround ...

3) The whole point of deep file is to get volumetric position of pixels (sort of). So you can add some 2D elements inside 3D elements, deepmerge them, do nice defocus and fog, etc). BUT, we still need, for example, rgb mattes to do local color corrections. These has nothing to do with deep data, and really not have to be stored as half float (we use png 8bts rgb for this). And this is these 'other' render elements which are not always used, can be re rendered later, render more later etc. Why they need to be really separate files.

[Dave_Wortley]

3dsmax is awful when it comes to different render formats and render elements, there are some secret stored settings within the render element dialog, it is possible to render MMEs in a different format to the main render but it is a real pain and requires a bit of a hack to do it.

I've been asking for years for Autodesk to fix this... It's totally possible and happens quite often to have a render saved with a .exr extension when the file internally is a PNG/TGA... I wrote a function for Deadline (which they've included) to help reformat the render elements if you do something like switch your output.

I'll add my voice to the request to be able to save main RGB as Float, ZDepth as Deep and MMEs as 8bit, we normally render quite a few MMEs!!

[vlado]

3) The whole point of deep file is to get volumetric position of pixels (sort of). So you can add some 2D elements inside 3D elements, deepmerge them, do nice defocus and fog, etc).

Yes, and this also has a side effect - the ability to extract any object perfectly, without the need for mattes (if you use object IDs or render IDs, at any rate).

BUT, we still need, for example, rgb mattes to do local color corrections. These has nothing to do with deep data, and really not have to be stored as half float (we use png 8bts rgb for this).

You get these mattes for free with the deep file without storing any additional data into it at all.

Best regards,
Vlado

[KiboOst]

We have thousands of objects in our renders, we don't do rgb mattes per object, but per materials or per group.
Example :
thisMetal objects : object ID 1
thisWood objects : object ID 2
thisGlass objects : object ID 3
theseVegetation objects : object ID 4
thisGroup objects : object ID 5
etc ...
Then we output multimattes per object ID, but these aren't "per 3D objects"
Compositing per object in such renders would take ages ...

Dave, as I said on the other forum, we set file name and file type per renderelement when using max VFB, and all goes perfectly fine.

[vlado]

Then we output multimattes per object ID, but these aren't "per 3D objects"

Exactly what I meant, yes.

Compositing per object in such renders would take ages ...

For sure, I wasn't suggesting that you do that

Best regards,
Vlado

[KiboOst]

Vlado, can't we have a VRayDeep render element that export deep data into an exr2 ? Maybe would need an exr2 writer for max ? Then we could use max VFB, have our render and elements in normal way, and in Nuke have DeepRead to the VRayDeep element, and a DeepRecolor from the beauty pass and all would be effective !

Didn't the vray3 beta had such RE ?

These workflow limitations are a real pain ...

[joconnell]

I've been asking for years for Autodesk to fix this... It's totally possible and happens quite often to have a render saved with a .exr extension when the file internally is a PNG/TGA... I wrote a function for Deadline (which they've included) to help reformat the render elements if you do something like switch your output.

Yeah I had this happen on max 2012, I thought it was fixed by now with a new file output module from autodesk? Either way the lovely Rens has some code that writes a 1 x 1 bitmap to force max to use the right format and the file to write correctly - http://forums.chaosgroup.com/showthr...624#post586624

[KiboOst]

Vlado, can't we have a VRayDeep render element that export deep data into an exr2 when rendering with 3dsmax VFB ? Maybe would need an exr2 writer for max ? Then we could use max VFB, have our render and elements in normal way, and in Nuke have DeepRead to the VRayDeep element, and a DeepRecolor from the beauty pass and all would be effective !

Didn't the vray3 beta had such RE ?

These workflow limitations are a real pain ...

Vlado, did you have a look at this ? Would really improve workflow to get this.