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heynewt
02-18-2009, 07:48 AM
I accidentally rendered a sequence out using the .tif FP setting instead of the regular .tif setting. I understand FP stands for floating point, and I vaguely realize that gives me more color info, but I don't understand what that buys me in post.

First of all the file sizes were 4X the normal file size. I brought the sequence into AE, it was all washed out, nothing like the preview window while I was rendering.

I managed to figure out (by turning off color management) how to get the sequence to look normal.

I'm just curious what all that extra file size gives me now.

Robert N.

vfxwizard
02-18-2009, 11:48 AM
I'm just curious what all that extra file size gives me now.


In general, floating point images give you more precision. Instead of 255 fixed steps per color component, you get an infinite number of intermediate steps. They also allow to express colors brighter than full white, and in this case the images are called HDR: High Dynamic Range.

The reason why it looked washed out is that deep formats like exr and FP tiff are meant to store linear light data, which has to be corrected for proper display on a monitor. The dreaded Gamma correction.

Turning color management off in AE disables this correction, so the render looks just like in Lightwave, but this will only buy you headroom for blurs and color correction -you'll have more informations to work with, but they won't be setup to make the most out of them. And unless you set AE to 32bit mode (alt-click twice on the 8bpc icon in Project panel), you won't even get this far.

On the other hand, if you are willing/interested in trying linear rendering there will be many advantages (proper light falloffs, radiosity behaving as expected, and very easy cg+live action compositing). The downside is that linear workflow takes a little time to get used to and has some strict rules to be followed. You have to change the way you surface and light scenes in Lightwave, so that Lightwave renders look wrong (dark and with strong contrast), but AE displays them properly.

On this forum there are some excellent posts from Gerardo Estrada and others about all this. Or Google "linear rendering workflow", there are some nice VRAY/Max tutorials that apply to LW as well.

One last thing, Lightwave specific: make sure Dither Intensity and Limit Dynamic Range are both turned off when using linear formats. They mess badly with FP images.

Hope this helps.

heynewt
02-18-2009, 12:12 PM
Oh, I didn't realize FP renders were creating HDR images. That's very cool.

I know only enough about linear workflow to be dangerous, but now you've really piqued my interest. I'm definitely going to read up on the process.

Though it sounds really difficult if you're having to animate and light for a render that looks deliberately dark. I guess you take all your cues from After Effects composition that's already been "treated".

So that's how they get the photorealistic CG mixed with live action footage. I always thought my own attempts suffered from a lack of having dynamic range in my CG images to alter them in compositing with enough "subtleness" to match the live action plate.

Now I realize what I was probably missing.

Thanks again, that was a great post.

Robert N.

toby
02-20-2009, 02:59 AM
Here's where the mind-numbing starts -
http://www.newtek.com/forums/showthread.php?p=809998#post809998

Stenna
02-24-2009, 05:44 AM
I accidentally rendered a sequence out using the .tif FP setting instead of the regular .tif setting. I understand FP stands for floating point, and I vaguely realize that gives me more color info, but I don't understand what that buys me in post.

First of all the file sizes were 4X the normal file size. I brought the sequence into AE, it was all washed out, nothing like the preview window while I was rendering.

I managed to figure out (by turning off color management) how to get the sequence to look normal.

I'm just curious what all that extra file size gives me now.

Robert N.

Thanks for info :help: