Author Topic: Understanding saving file: CXR / .exr / .rla?  (Read 807 times)

2020-10-28, 05:35:51

caspian

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If I save a render from the VFB it either spits out a .exr file (which I can open in Photoshop) or it saves a .rla which I can't do anything with. My guess is it's to do with multi-pass or shadow catcher as in both instances when I'm using those I end up struggling to export a file I can composit with.
What is the .rla file for and how can I use it.

Many thanks

(I'm on Mac)

2020-10-28, 11:59:37
Reply #1

TomG

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What are you using to save, Save, Save All, or Save CXR? That is if you are using Save in the VFB - or are you using Save in the Render Settings dialog? The Save in the VFB asks you to pick file name and file type, so it would be up to you whether you choose a .rla or not (I've never used rla, not a format I have heard of or am familiar with). AFAIK there's no way you would be "forced" into using .rla.

Also, which version of Corona, which version of C4D :)

2020-10-28, 21:25:35
Reply #2

caspian

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Corona 6. R23.

The VDB's interface promotes saving as CXR as it's the only file format actually listed specifically, with the other available formats under a more generic 'Save All'. It's totally possible I'm missing something basic here.
A very simple scene. Save > Save CXR. Sometimes it will save out a .EXR file that I can open on photoshop. (Still not sure why is says it's saving a CXR when it saves an EXR, what is the difference?) and other times (I can't seem to work out when/why) it saves out a .CXR file that I can't open
Or I decide I want to save out the alpha as well > Save All and it suggests is is saving out an OpenEXR which this time saves out a .RLA file.

I realise I can save out PNGs but I'd really like to understand what the CXR/RLA/EXR files are for and what I can use to open them as they seems t be important to Corona, otherwise why have them so prominently in the UI?

2020-10-28, 21:47:26
Reply #3

TomG

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Could you video capture what is happening for you? It's hard to tell from just word descriptions alone.

RLA is not related to Corona at all (and neither is EXR of course). Info on RLA is here (I just Googled it :) ) https://www.fileformat.info/format/wavefrontrla/egff.htm, so it's a wavefront thing (and so, very old and certainly nothing we've ever used).

Neither is given any special prominence in the UI here, they are just two file types among the many if I do a save and click the drop down list of file types (order of file types in there is set by C4D I would think, perhaps even EXR being the default, not sure on that).

CXR is just the EXR format with extra data added for Corona to be able to resume rendering, handle LightMix, and denoising. It's listed specifically for that reason, as it is Corona specific, and so not included in the file type list that C4D has natively. I don't recall ever seeing it save as an EXR if "Save CXR" was selected. Might be worth sending in the scene too, along with a video grab of what happens for you.

2020-10-29, 00:59:53
Reply #4

Cinemike

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RLA is a format supported by C4D natively and can be saved from the picture viewer. That's why it is probably available in the VFB save menu (see below), too.
I can only imagine that caspian somehow accidentally "slips" into the RLA entry when he tries to save from the VFB. All other formats should be available from there, too.

CU
Michael

2020-10-29, 02:29:46
Reply #5

caspian

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Here's a screen capture
1st Save by clicking on Save and saving it as default OpenEXR. The saved file is .RLA (I can't open this)
2nd Save by Save CXR. Only option is Corona EXR. Saved file is .CXR (I can't open this)
3rd Save by Save All. Again saved as OpenEXR. The saved file is .EXR which I can open.

I don't understand what the purpose of the RLA and Corona EXR files, although as I mentioned before they are the formats that unless I deliberately avoid it saves it as.

https://www.dropbox.com/s/lhngvdb2mf249hn/Corona-saving.mp4?dl=0

2020-10-29, 02:39:09
Reply #6

caspian

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Here are two more save tests.

1st save (x) I don't select the save format which is already set to the default OpenEXR. Resultant file is .RLA
2nd save (y) I select the already selected default. Resultant file is .EXR.

Maybe this is a bug (on Mac)?

https://www.dropbox.com/s/hljgd5xpak02yhr/Saving%20part%202.mp4?dl=0

2020-10-29, 04:28:13
Reply #7

TomG

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TY for the videos!

CXRs you can open in the Corona Image Editor, or use to Resume Render, or rename to EXR to open them in other applications. As noted this is the Corona specific version of EXRs, for Corona to use (CIE, Resume Render), so only Corona can open them.

For the rla, I definitely don't get that on Windows. What happens if you uncheck save alpha, as I am not sure EXRs use alpha so it could be it saves an extra file for the alpha and for reasons known only to C4D it picks rla (the save dialog here is C4Ds save dialog, invoked from Corona, so anything it does is in fact C4D at work, as I understand it, and not Corona specific). What happens if you save from the C4D picture viewer, the same thing, or something different? Also, what happens if you pick something that is not EXR and does support alpha, like PNG? Does it still create an rla?

As noted too, the rla is nothing to do with Corona either, it's a wavefront file, so very old and never ever used by Corona to save, load, or anything else, now or at any point in the past :)


2020-10-29, 04:36:16
Reply #8

caspian

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Answers:
The test scene doesn't have the Alpha channel checked in the Render Settings.
If I select PNG it renders PNG as expected (no rla file)

2020-10-29, 13:02:21
Reply #9

TomG

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It's not the alpha in the scene I was curious about, but the "Save alpha" checkbox in the file options dialog that pops up. Rather than just hit OK when that comes up, what happens if you disable the Save Alpha checkbox in that and then hit ok?

2020-10-29, 20:46:02
Reply #10

caspian

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Answer:
Unchecking Save alpha still creates an .RLA file.