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spiralof5
09-06-2007, 08:52 AM
Does exr even need to be used if you are going to compress your movie with mpeg4 quicktime, divx, etc. in a program such as after effects?

Thanks

Scott

floze
09-06-2007, 11:06 AM
...no?

What's your actual issue? If you dont need it dont use it..

If you need more information on the OpenEXR format check out http://www.openexr.com/.

spiralof5
09-06-2007, 10:46 PM
I get that it saves humungous amounts of color range and multiple 'other' channels rather than just your standard RGB and A 0-255. These are used in post production to do things in which a regular targa or jpeg can't.

My issue is this. Aside from the extra channels, am I getting a better render? If so, aren't I going to just lose that when it becomes compressed into divx or mpeg4 anyways?

My second issue is this. I've downloaded the program ProEXR for Photoshop CS3. So how come when I render out at .exr in Maya, I'm only getting RGB and A, which I can get with Tiff and Targa?

Thanks.

Scott

djx
09-06-2007, 11:40 PM
Aside from the extra channels, am I getting a better render?
No, the render will not be better, unless by better you mean you want 32 bit for some reason. Even the extra channels dont magically appear just because you render to exr - as you have already discovered.

Consider that even though divx (or some other highly compressed codec) will be your final output format, you may first want to work on your rendered components in a compositing application. That is when there are advantages to working with higher bit depth, and possibly some convenience to having all the layers in one file if your application supports this.

Try a search for ctrl.buffers or puppet's p_MegaTK

-- David

spiralof5
09-07-2007, 06:51 AM
My second issue is this. I've downloaded the program ProEXR for Photoshop CS3. So how come when I render out at .exr in Maya, I'm only getting RGB and A, which I can get with Tiff and Targa?

Even the extra channels dont magically appear just because you render to exr - as you have already discovered.

Well that's what ProEXR is supposed to be. It's an external plugin that is supposed to open your .exr and allow for CS3 to see those extra channels. Can shake open these with no problems?

The second quote doesn't even make sense. I'm rendering with a physical sun/sky and I should have the -value to 64,000 whatever values when using IBL and rendering sun/sky to exr. Why the heck would Maya even allow to render .exr if there is absolutely no purpose in using them because they don't allows "extra channels" "magically appear just because you render to exr"? I get that ctrl_buffers can 'stuff' your channels but my problem, again, is that I'm only receiving RGB and A when everyone else at LEAST gets RGBA and Z (or depth).

Sorry if I sound harsh it's just I think you confused me more. Your first answer helps though. If I'm not doing post processing then don't worry about .exr. Got it.

Thanx!

distract
09-07-2007, 07:15 AM
we used EXR on some of the last projects. The main reason was color correction, you can take the image where you want in the post without loss of detail. Itīs not a magical format, merely a container, where you can stuff your channels into. if your doing no post then thereīs no need. if you like using gamma/gain/exposure later on, i would just give it a try with a half float EXR, and you can easily see why itīs fun to use compared to 8/16bit...

spiralof5
09-07-2007, 07:45 AM
we used EXR on some of the last projects. The main reason was color correction, you can take the image where you want in the post without loss of detail. Itīs not a magical format, merely a container, where you can stuff your channels into. if your doing no post then thereīs no need. if you like using gamma/gain/exposure later on, i would just give it a try with a half float EXR, and you can easily see why itīs fun to use compared to 8/16bit...

O.k. but the question remains. What post program are you using? Why do I only get RGB and A when I render exr when everyone else seems to be getting at LEAST RGBA and Z (or depth). What do I have to do to be able to adjust gamma/gain/exposure in post? Shake?

Are you talking about stuffing render passes into the channels? Is the only way to do that through ctrl_buffers, p_megaTK?

Yes, in the future I will be dealing with post. I have to deal with everything due to the fact I'm a one man freelancer so I have to learn freakin' everything. So far I've found rendering to be the absolute toughest issue because everything changes so frequently. EXR is fairly new but everyone is talking about how great it is. Yet I haven't been able to grab ahold of any good tutorials. Anyone know of a few?

distract
09-07-2007, 08:24 AM
using fusion and combustion (although combustions need some workarounds and is not really easy to work with that). fusion is quite good, nuke seems to be still better for the extra channels.

actually you could adjust the color stuff/exposure using a photoshop macro (just as an example).

iīm not experienced in stuffing the channels into EXR in maya. weīre mostly using max and vray, but on the project at the moment itīs maya, but rendering is done in renderman somewhere else. with a lot of extra information like world space XYZ, etc.

I just thought I jump in and comment about the general EXR use.
float colors are also not "better" but better for editing without loosing details. set the bitdepth to float and do a still-render and try to brighten dark shadow areas in photoshop and youīll see the fun in that...

spiralof5
09-07-2007, 08:00 PM
I just thought I jump in and comment about the general EXR use.
float colors are also not "better" but better for editing without loosing details. set the bitdepth to float and do a still-render and try to brighten dark shadow areas in photoshop and youīll see the fun in that...

Well definitely thank you for your comments....as well as everyone else. This issue is still open to me so I hope others join the convo. That's awsome, I actually saw a quote about Francesca Luce's ctrl_buffers saying that when you are saving to exr or hdr you really are saving high dynamic range pixel data, so it is different and yes, better. Maybe the eye can't tell much but as you said, play with the shadow/highlight you can see what's up.

So for others reading this, how do I get the Z depth channel when I render to exr?

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