PDA

View Full Version : Does this Depth Of Field look as good as it can be?



rdolishny
03-09-2009, 06:55 AM
Take a look at this still image and let me know if this is as good as it's gonna get with LWs DOF.

I've never noticed the grain before on moving images with DOF on, but in this case I need to render out stills without motion blur.

I'm using the Perspective camera, AA set to 3, Adaptive Sampling is ON, with a shallow f-stop of 1.2.

Please, what is your favourite setting for really smooth DOF?

archijam
03-09-2009, 07:03 AM
Nope.

Try turning your Threshold down, I get good DOF with settings something like this:
AA 4, Box/Fixed
Threshold 0.01
Oversample 0.1

Soft Filter OFF

(these are from memory, but give them a shot)

rdolishny
03-09-2009, 11:17 AM
Thanks archijam. Turning down the threshold seems to be the key. I am out of the office at the moment but eager to give it a try.

- Rick

archijam
03-09-2009, 05:10 PM
Unfortunately, that means turning up the render times ;), but there's always a trade off ...

jameswillmott
03-09-2009, 05:30 PM
You could try the Gaussian filter or upping the Oversample distance to help denoise everything a bit more...

toby
03-09-2009, 09:01 PM
I agree with Gaussian, for animation. But *not* AS threshold of .01! Below .02 the rendertimes will double with *no* increase in quality. A bunch of us found this out in another thread, I'll find it if you want. There's no substitute for higher AA!

Smooth DOF with this much blur will always be expensive (except maybe with XDof), if you can do some of it in post you'll be in great shape.

rdolishny
03-09-2009, 09:45 PM
Thanks for the tips and especially the hint at a previous thread (http://www.newtek.com/forums/showthread.php?t=94378&highlight=depth+field). I don't know how this escaped me.

I am in the middle of a 20 minute render (it was over 10 so not too bad of a hit) and I can tell with the Adaptive Sampling at 0.3 it's looking great already.

Now, how do I set it back to default! :)

AA: 5
Adaptive sampling: 0.03
Oversample: 0.7

A few have mentioned doing it in post, I just don't know how to generate a depth map and how to use that in After Effects. I know LW now has an EXR saver I think that will help ... but I haven't come across any total workflow articles or videos that apply to Lightwave. Still looking.

Thanks everyone, my renders are looking better already thanks to you!!!

rdolishny
03-09-2009, 10:47 PM
I agree with Gaussian, for animation. But *not* AS threshold of .01! Below .02 the rendertimes will double with *no* increase in quality. A bunch of us found this out in another thread, I'll find it if you want. There's no substitute for higher AA!

Smooth DOF with this much blur will always be expensive (except maybe with XDof), if you can do some of it in post you'll be in great shape.


But check out this quote from the LW manual:



"For most images, it is best to set the antialiasing samples to 1 when adaptive sampling is enabled"

I have done some testing and it appears this is true! I'll post a sample tomorrow but it's late and a hirez test will take a few minutes!

toby
03-09-2009, 11:36 PM
My point was that if your aa is not good enough, going below .02 will not help you, raising the aa level is solution in that case.

I find that hard to believe anyway, I'll test it too.

archijam
03-10-2009, 01:26 AM
I should spend more time on here, eh? ;)

toby
03-10-2009, 01:40 AM
I should spend more time on here, eh? ;)
Yes you should, having 'a life' is totally overrated =)

toby
03-10-2009, 01:55 AM
Here's the thread where I learned that 1 sample will can't give you max quality:
http://www.newtek.com/forums/showthread.php?t=91690&highlight=hey+guys&page=3

and it makes sense, adaptive relies on edge detection, it'll probably never be as good as just aa'ing every pixel. I found that One sample at .01 adaptive still left jaggies in this scene.

rdolishny
03-10-2009, 04:20 AM
Toby, I can't access the link. The forum reports I don't have sufficient
permissions.

Your logic as per AA before AS gets at the image makes sense. I'm rendering another HD test image to take a closer look.

- Rick

toby
03-10-2009, 07:11 PM
Oh sorry that's in an old beta forum.
To summarize, I noticed someone was rendering the 'museum' lighting challenge with 12 passes aa, .05 as. I asked him if that was necessary, thinking that 1 sample would cover anything with a low enough threshold. Turns out the 12 sample was faster and better looking than 1 sample set to .01 as. Another experienced guy posted that he uses 25 passes with no adaptive to get full quality. But that also depends on your construction filter.

rdolishny
03-10-2009, 08:50 PM
Thanks Toby for looking that up. I think the Anti Aliasing issue is an ongoing one, complicated for me being a legacy user with experience on the old Lightwave camera with the exclusive multiple-pass option.

After rendering three HD images with three slightly different settings, I have determined for my purposes there is NO difference between 1, 3 or five levels of AA using the Perspective camera. Render times were within five percent of each other, so virtually the same.

The payoff came by tweaking the Adaptive Sampling Threshold. A setting of 0.03 rendered more than acceptable results, and with an AA of 1 render time was fine. Just on a lark I tried a rendering at 0.02 and found it was noticeably better than my first test at 18 minutes, but only just a bit.

The attached file is the first rendering with AA=1 and AS=0.03.

All test images 800x600.
Camera=classic
Oversampling=0.5
Photoreal motion blur 1 pass.

AA=1
AS=0.03
Render time= 18 minutes *

AA=5
AS=0.03
Render time=32 minutes *

AA=1
AS=0.02
Render time=30 minutes **


* identical image quality results
** slightly better DOF softness

toby
03-11-2009, 02:45 PM
Rendering with more aa passes will result in fewer adaptive passes, so it is certainly possible to have the similar render times. Personally I'd choose the higher aa if it's the same speed, it's more likely to cover all bases than adaptive sampling. At digital domain we were not allowed to use adaptive at all, for best quality.

I think the dof could be better, but whether it's worth the additional time is up to you.

These are very good tests to do, because it will be different for every scene/project. You should be able to do quicker tests though, for example turn off radiosity when testing aa and dof, and vice-versa, and/or using limited region.

rdolishny
03-11-2009, 03:04 PM
I'm ashamed to say I totally forgot about limited region! :bowdown:

rdolishny
03-20-2009, 04:09 PM
I just wanted to thank all of the participants on this thread for helping me meet my deadline and generate images that really blew me and the director away.

You can read about the process, see some wires, and see the commercial here (http://rdolishny.blogspot.com/2009/03/doritos-when-nacho-met-cheese.html).

Thanks again! You guys rock!

- Rick