V-Ray raw image file - exr missing render elements

[AJ Jefferies]

I've just rendered a large format image and opted for EXR as the file format to save some time converting the vrimg file.

The help file says:

If you specify an .exr extension, V-Ray will write out a tiled OpenEXR file that can be used directly by 3ds Max or other compositing applications. The file contains all render elements for the image. When you click the Browse button you can specify the file name whether you want the image saved in a 16bit or a 32bit .exr.

However when I open up the .exr file I can't see the render elements in any of the channels. At first I thought this might be a limitation of Photoshop, so I opened it up through the VFB but still can't see any of the render elements.

Is there something I'm missing should I have stuck to the vrimg file format?

This was a 12'000 pixel render that took all day, so it would be really good if I don't have to re-render it again!

[vlado]

The VFB will only load the RGBA channels for formats different from .vrimg, so it's not an indication of anything. Did you try the exrheader tool to see what channels are in the file? Let me know if you don't have that.

Best regards,
Vlado

[AJ Jefferies]

Hi Vlado,

Thanks for the quick response. I didn't have the exrheader tool but found a compiled binary on the openexr.com site. It gives me this:

channels (type chlist):
A, 32-bit floating-point, sampling 1 1
B, 32-bit floating-point, sampling 1 1
G, 32-bit floating-point, sampling 1 1
R, 32-bit floating-point, sampling 1 1
VRayNormals.X, 32-bit floating-point, sampling 1 1
VRayNormals.Y, 32-bit floating-point, sampling 1 1
VRayNormals.Z, 32-bit floating-point, sampling 1 1
VRayWireColor.B, 32-bit floating-point, sampling 1 1
VRayWireColor.G, 32-bit floating-point, sampling 1 1
VRayWireColor.R, 32-bit floating-point, sampling 1 1
Z, 32-bit floating-point, sampling 1 1

Which is promising!

How can I extract these channels from the exr?

Thanks again

[vlado]

I guess it depends on what program you want to load it in. But if worse comes to worse, 3ds Max > View image file > Select the .exr file - here you can also select which element to be imported and then resave that element separately.

Best regards,
Vlado

[Morne]

If you have the OpenEXR plugin in photoshop, then you can read all the channels apparently. This is built into after affects already. But Vlado's suggestion is best if you dont want to mess around...

[AJ Jefferies]

Thanks guys, I'd completely forgotten that we had bought the ProEXR photoshop plugin. I will dig it out.

I've come in this morning to discover a render I set up overnight has crapped out around 90% of the way through. Because I had set the output to EXR there's just a 170KB file, whereas with the vrimg format there would be some salvageable data. I completely blame myself for trying something I'd not tested on a deadline but it would be good if there was a warning or some on screen information saying that the exr will no incrementally save as it renders.