Using imgtotiledexr for mipmap exrs and use in Vray.

[Intuition]

So I am attempting to get the benefit of using mipmap tiled exrs in Vray to save ram usage and scene export time.

I did convert a whole folder of images from PNG, JPG, and TIF into EXR.

I couldn't find much documentation on the settings as far as why I would set say the tile size anything other than 64.

The pros and cons or 16/32 bit

Why/When to use certain compression methods.

Though I did read this...

http://help.chaosgroup.com/vray/help...g2tiledexr.htm

My issue is that when I made the exrs and loaded them it made maya very unresponsive.

On top of that it took much longer to export the exrs than when I was using the tifs, pngs, and jpgs. Like from less than a minute to test render to 15 minutes.

What specific settings should I be using in order to see the gains with using mip map exrs?

This was all automated at a facility for me and now freelance gigs are having me set it up for myself.

Thanks for any information.

[vlado]

If you are looking to convert 8-bit textures, it might make more sense to use maketx from the OIIO library, as .tx files can store tiled 8-bit images. This makes them twice smaller than 16-bit OpenEXR files both on disk and for rendering.

In any case, can you explain a bit what you mean by "export the exrs"?

Best regards,
Vlado

[Intuition]

Oh sorry, yes by export I mean when Maya is exporting the scene to Vray. When I press render and watch the maya output window I see that it is vry slow to get through the exr images before rendering. This makes me think I did not set up something correctly in Vray so it knows to use the tiled EXRs correctly OR that I did not make the tiled EXR s with the correct settings in img2tiledexr settings. Like maybe I should have left it 16bit or smaller than 64 size.

[Svetlozar Draganov]

Hello,

I've just did a comparing test between JPG and EXR version of the same scene but unfortunately there weren't any noticeable differences in the exporting times, I actually have feeling that exporting EXR-version is slightly faster than JPG-one.
Would it be possible to send us your version of EXR and non-EXR of the scene for investigation (we could provide FTP if needed) ?
Let us also know the exact versions(including service packs and etc) of Vray/Maya you are using.

Thank you very much in advance.

[Intuition]

It may have been that I was not using the scanline compression style for EXR. I know that in the past if I had an 8k map in tif or png vs an 8k map in exr the exr would export quicker since the mip map function would relieve vray of having to load it into ram in favor of grabbing the data it sees in whichever bucket it was rendering. Is this how it still works? Or is it performing this for all images? At the previous facility I remember having to make sure we used properly mip mapped exrs to ensure much less ram usage than say the equivalent large png or tiffs.

[Svetlozar Draganov]

Yes this is the way it works, it loads only information needed for the current bucket. However, LC calculation is performed for the entire image not bucket by bucket so if you are using it Vray will load all the textures at the very beginning.
What type of compression you've used for that particular case.

[Intuition]

So, it does do this for all images types or only mip mapped exrs? I am trying to assess if I should go to all the trouble of converting most of my images to EXR or if Vray just does this for all images by default?.

[vlado]

I am trying to assess if I should go to all the trouble of converting most of my images to EXR or if Vray just does this for all images by default?.

No, we do not do this automatically. Also, I wouldn't hurry to convert everything unless there is specific reason to do it (like memory problems with rendering a scene). Finally, for 8-bit textures, it might be better to use maketx to convert them to tiled TIFF textures - they can be 8-bit, which saves quite a bit of RAM compared to 16-bit OpenEXRs (twice less, to be precise).

Best regards,
Vlado

[Intuition]

I want to make some kind of documentation for this since its still a semi unknown benefit for use with large scenes.

Questions.

1. What kind of compression is best for the mip map exrs?
2. Is there a specific MEL script or check box in Vray UI I should run in order to get Vray to load the mip mapped exrs and mip mapped tifs this way?
3. Do I need to use the vray mip map filter on the image files node in order to use this feature?

I want to automate this process for our lookdev team so will be creating some scripts for image conversion, render settings, etc. that will optimize this for out very large scenes.

[tashko.zashev]

I want to make some kind of documentation for this since its still a semi unknown benefit for use with large scenes.

Questions.

1. What kind of compression is best for the mip map exrs?
2. Is there a specific MEL script or check box in Vray UI I should run in order to get Vray to load the mip mapped exrs and mip mapped tifs this way?
3. Do I need to use the vray mip map filter on the image files node in order to use this feature?

I want to automate this process for our lookdev team so will be creating some scripts for image conversion, render settings, etc. that will optimize this for out very large scenes.

Hi,

Regarding question 1) I prefer the Zips type, but you can make a test and see which one is more suitable for your workflow.
2 & 3) Only have to set "Mipmap" filter in the Maya File node.