Yesterday I posted a handful of links to a very cool OpenEXR site. So I figured today it would be a good idea to infect the uninfected with EXR fever. And talk a little bit about what it is and why it’s so kick ass. Plus, I really needed to take a break from the awesomeness that is…”Super Mario Galaxy” for a second. So…here we go.

Now what is OpenEXR you ask? Well before I mess this explanation up, click the link below before you read any further so the genius’s at ILM can explain first.

OpenEXR

You all done? Alright, now it’s my turn. OpenEXR is a completely lossless, floating point, multi-channel file format which is the offspring of it’s native Cineon file format. Which is also lossless and lives in the logarithmic color space, but doesn’t have the added sweetness of having embedded passes in just one pretty file like OpenEXR does.

Alright, now that I’ve told you what it is…why is all of that so important?

Well, lets start with the first advantage listed…Being lossless. Now imagine you’re at Kinkos, and you need to make a copy of a picture. But it’s not the original picture. It’s already a copy of the original. Now when all is said and done, that copy of a copy won’t be as sharp and pretty as the previous, right? Well the same thing happens in a Visual Effects pipeline. If you keep rendering out sequences, that are made up of already compressed sequences, your final copy ain’t going to look that great. So the solution? Use a file format that’s lossless. And what gives it the ability to be lossless unlike a .tiff or a .tga? Well…you guessed it…floating point.

Now what is this “floating point” I speak of? Well remember in math class when you’d get those damn decimal points that would make things just a little bit harder? Well in the world of OpenEXR, guess what? They’re your best friend. Because they give your image the ability to store more data in the RGB than a conventional image. The term for this is a High Dynamic Range Image, or HDRI.

If you really want to delive deep into this end of the pool, check out this link…floating point.

Thinking about all that math just made me go cross-eyed. Now where was I? Oh ya, the fun part. The greatest part. The part that makes all the other parts look lame. Multi-Channel file support. Doesn’t that just sound like music to the ears? Mmmm. Anyways, like all Compositors know; one beauty pass just doesn’t cut when it comes to finishing that shot that was due yesterday. It takes a bunch of different passes with weird names like “Diffuse”, or “ZDepth”, or even “Ambient Occlusion!” So what we have had to do in the past is read in each one of these passes individually, and combine them in a tree that can get really messy, really fast. But those untidy days are no more! Because now we have to option to use the OpenEXR file format to put all of the render passes we need into ONE pretty little read node. Which is just one of the many reasons why I love Nuke. Because it’s made to work with embedded channels.

Now if you’re like me, you want to know where you can get your hands on these OpenEXR files, and start rendering till your face goes blue. Well luckily for you, the new Maya Unlimited 2008 (my 3D software of choice) comes with render support for OpenEXR! And there are tons of plugins for all of your other standard 3D apps like 3DSMax and Houdini. So just set up your render layers, select .exr, and render away!

Alright, well that’s pretty much it. For those who have never heard of this before, do yourself a favor and go check it out. And those of you who had, well what are you doing still reading this? You already know how awesome this is!