Best compression with img2tiledexr for V-Ray 3 rendering?

[Fredrik Averpil]

Hi,

I'm thinking we should convert all file textures to EXR using the img2tiledexr utility prior to rendering (in V-Ray 3).

What would be the most ideal compression setting for performance vs disk usage?
Since the compression type "ZIP" is default, I'm assuming this is the best trade-off between disk usage and V-Ray performance?

[ivaylo.ivanov]

I think only the new compressions - dwaa and dwab may save disk space, but they are not widely supported. ZIP is also somewhat the star in compression/performance ratio and this is why it's so widely used.

[t.petrov]

I'm thinking we should convert all file textures to EXR using the img2tiledexr utility prior to rendering (in V-Ray 3).

Keep in mind that OpenEXR doesn't support 8bits per channel, the minimum is 16bits.
So if you have mostly diffuse like textures it will probably be better to use tiled TIFF files.

[Fredrik Averpil]

Ok, thanks.

Regarding tiled TIFF files... do you provide such a conversion utility with V-Ray or are you aware of any such utility e.g. bundled with Maya?

I'm doing a benchmark here now where I render a large scene (texture-wise) with textures made up of a variety of image formats. Then I'm going to compare this against the same scene but where all textures have been converted to tiled EXRs (converted with default settings using img2tiledexr).

[t.petrov]

maketx or txmake are two utilities that can generate them.
OpenImageIO has maketx in its package I think.

[Fredrik Averpil]

Allright, thanks!

[Fredrik Averpil]

Hi again,

I think it would be great if you would consider bundling maketx together with V-Ray. Do you think it could be possible?
I just mean you will drop it into the V-Ray tools bin folder, like you do with img2tiledexr.

[t.petrov]

We can do it of course, but we'll have to spend additional time on supporting it, updating the library, rebuilding, retesting and so on.

[Fredrik Averpil]

Maybe you're right. Perhaps it's better for you to focus on more important things. I need to compile OIIO anyways.

Is there a specific EXR version requirement I need to make sure is the same in V-Ray vs OIIO?

[ivaylo.ivanov]

Just use the latest OpenEXR library sources 2.2

[Fredrik Averpil]

Great, thanks.