[RonB]

I am sure this has been gone over before but I could not find anything in a site search.
Wondering if and when Maxwell will be using EXR file format? Been reading Blochi's HDRI Handbook and it seems EXR is a very elegant format for imaging. BTW, I think Blochi's book should be required reading for anyone doing anything in 3D imaging or CG imaging of any sort...it's like a walk in the park, very easy read and very informative.

Any references to past threads on the subject appreciated, and any comments as well.

Thanks,
Ron

[Bubbaloo]

What's the book's title?

[JCAddy]

Agreed, Maxwell should be able to utilize EXR full float format. We use EXR's almost exclusively here. It's great being able to adjust your exposure properly in photoshop after rendering.

[Bubbaloo]

What's the book's title?

[RonB]

The HDRI Handbook....

http://www.hdrlabs.com/book/index.html

Also check out the entire site...very cool, very cool, all free!

http://www.hdrlabs.com/sibl/index.html

http://www.hdrlabs.com/cgi-bin/forum/YaBB.pl

He's a genuine unsung hero as far as I'm concerned...

Cheers,
Ron

[Bubbaloo]

Thanks, I'll check it out!

[RonB]

I was kind of hoping for a comment from one of the NL folks...

Is EXR not worth looking into, are you, are you not?

EXR seems to be in the lead at the moment because everyone wants to be associated with Lucas and ILM. But aside from that EXR is a very workable format. The fact is we will all be operating in some sort of high dynamic range imaging besides HDR, which is getting a bit long in the tooth. EXR is working now and I think NL needs to support it now. It's post benefits are way better than anything else we have.

Why not?

Come on folks make some comments...

Ron

[Bubbaloo]

With me being too damn lazy to do my own research, what are the main differences between EXR and the other floating point formats?

[RonB]

In a nutshell:

Written by Florian Kainz at ILM in 2000 for their in-house apps, release to the public in 2003 as open source. The only image format to ever win an Oscar! Each color channel is 16 bits adding up to 48 bits...don't confuse that with the traditional 16-bit format though. The old 16 bit is regular numbers and this one is floating-point numbers. The 16 bits are split into 1 sign bit, 10 mantissa bits, and 5 bits for an exponent. The mantissa allows 1,024 different color values per channel adding up to over a billion possible colors...independent from the exposure. So there are 1 billion colr values per exposure value. the dynamic range is carried in the exponent so OpenEXR can carry about 32 EV's...everything in nature if we we were able to view it all at once, from the Sun to the faintest star we can perceive is about 44 EV's. The current HDR, Tiff and other 32 bit floating point formats bloat the app and slow them down as we all have experienced. The OpenEXR with it's trimmed down 16 bits loads and saves way faster and it is natively supported by graphics cards like NVidia and ATI. The next gen image editors will be able to utilize the onboard shader language of the graphics cards and take the heavy lifting from the CPU. There won't be any difference speed wise working with HDR than there is with LDR now. Plus PIZ and ZIP compression works with it too.

The real kicker is OpenEXR is the only HDR format that can carry arbitrary channels. So you can include an alpha channel, and depth, shadow, motion,material, vectors...whatever you want. These channels have different compression, can be 16 or 32 bit and even different pixel resolutions. You can fine tune every single aspect of a rendered image in your compositing software. Another cool thing is the separation of the pixel size to the viewer window. You can have say a 100 pixel margin all around the frame of the image, the out of frame pixels are invisible. But when you use a large-scale filter like Gaussian Blur or even camera shake you don't get that standard side of the frame fuck up on the image...cool A? Pixar has switched to OpenEXR exclusively dumping their their own image format. They wrote a new compression scheme for it called PXR24. OpenEXR is a work horse of a format!

O.K. so he goes on to say that the only reason not to use OpenEXR is if your favorite software does not support it...in which case to sit down and write a complaint letter to the company and go on using good ol Radience until they do...

Hence my thread.

Hope that helps...get the book, there's lots more.

Cheers, Ron

[tom]

Maxwell has EXR input support for IBL environment and HDRI emission.

[Bubbaloo]

If I understand correctly, though, output is what he's asking for, right?

[RonB]

That's right Bubba, output is what it's all about. Image based lighting these days is really a non-event, it's the utilization of the format in the entire pipeline that I am talking about. Maxwell is a wonderful renderer but it is a part of the process not the end all be all. The tools that this format brings to the table allows us to take our Maxwell renders to finer levels than we can now. Plus the other obvious benefits it offers through the pipeline...faster image maniulation, faster saves, less storage, no image degradation etc.

Seems to be a format to use. There of course is the fact on the NL side of coding...but that is a fact of the industry. There will always be a new and better tool to be considered and included if you want to stay relevant.

[rivoli]

even though I perfectly see what you mean, and second exr support, multichannel exrs are in a way more than one usually needs.
exr it's the perfect format when doing a lot of compositing and post work (where you almost don't even need a beauty pass), maxwell clearly it's not the kind of renderer with which you'd work if that was the case.
and there are very few applications that deal with multi channels exr correctly and natively, nuke and fusion off the top of my head. ps can't read any other channel than rgba, and neither can ae. you'd need to buy a plugin to have them working, kind of.
with maxwell you usually have your image straight out of the renderer. well, sweeping generalization I know but I hope you get what I mean.
but this of course it's only a part of the advantages exrs can offer, smart compression methods or half float output being others.

[RonB]

Yes, I get your point rivoli...but I also disagree that it is a bit too much of a good thing. Compatibility is widening and as you say there are plugins available presently and more coming. The benefits to OpenEXR are just too many to ignore....and I predict it will become the standard imaging file format in the very near future.

Adobe has a basic problem to overcome with Photoshop's massive core rewrites because it operates on the premise that images are 8 bit gamma encoded. HDRI 32 bit sweeps that off the table. So it's taking a re-write of the entire program from the ground up. But you can bet your bippy that that's exactly whats going on at Adobe, and it won't be long. After all John Knoll wrote the basic code for Photoshop when he was in collage and developed the core at ILM. His brother is still on the PS credits so Knoll has kept his hand in there. ILM/EXR/ILM/JohnKnoll/Photoshop/EXR...doesn't take much of a stretch to connect those dots.

As far as composting goes I think Nuke leads the way at this time with up to 64 channels of OpenEXR supported. I think we will be seeing bunches of others come on board as well as new gen image editors...there are notables out there now for editors, Artizen HDR, Photomatix, which is a good program.

Cheers,
Ron

[rivoli]

The benefits to OpenEXR are just too many to ignore....and I predict it will become the standard imaging file format in the very near future.

agreed, and in a way it already is a de facto standard. but it seems to me not in the field toward which maxwell is actually targeted, arch and product viz that is. so I can see why the developers see that you must offer support to it when it comes to ibl, but maybe don't feel the urgency to support it as output.
but anyway, with this being said I'm with you on this one.