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LordIron2k
12-21-2003, 06:22 PM
Hi guys

Ive done some tests with Digital Confusion and i got these
weird artifacts.

http://thinknerd.de/~sadrine/WTF_dof.jpg


can someone/explain what i did wong?

I played only with the focus parameter to get a good result.

policarpo
12-21-2003, 06:58 PM
did you set a Null object in the scene for the camera to focus on?

that usually helps with digital confusion.

LordIron2k
12-21-2003, 07:05 PM
yes i did.

The NULL should be at the trunk

policarpo
12-21-2003, 07:12 PM
very weird.

you can also try messing with the scale of the scene.

sometimes if a scene is too small Digital Confusion freaks out.

Also...what is your lense F-Stop and Blur size set to?

LordIron2k
12-21-2003, 07:15 PM
thx polycarpo i think the size of the scene was way to small and the F- Stop settings was at (0.05) but what did u mean with Blue size?

policarpo
12-21-2003, 07:25 PM
I meant Blur. :drool:

also...try the F-Stop rate of .1 first, and then slightly go down from there...it might be too small of a stop for DC to handle in your scene.

Here's a sample using the NULL located near the trunk and the Lens F-Stop set to 0.1


http://www.policarpo.us/samples/porsche.jpg

LordIron2k
12-21-2003, 07:26 PM
ok i got it. I resized the car and set up the parameters corectly.

this comes out

http://thinknerd.de/~sadrine/dof_right.jpg

policarpo
12-21-2003, 07:29 PM
sweet dude.

looking good.

just keep tweaking the f-stop value until it gets right on the money for your shot.

i would suggest turning off AA for your preliminary tests as well. :)

Also, whenever you can afford it, get X-DOF from Evasion3D...it is a great plugin for LW.

:)

pixelranger
12-21-2003, 07:57 PM
Policarpo: I've heard X-Dof is a great plugin, but I've also heard that it seems to have problems keeping thing crystal clear in the focused area? Is it really as good as some claim?

policarpo
12-21-2003, 08:34 PM
Hrmm...i haven't really experienced anything like that. Have a look at their gallery of images generated using X-Dof...they show quite a few samples of what is possible using x-Dof.

here's a goofy sample...things still feel pretty sharp to me. the camera is focused on the ninja.

http://www.policarpo.us/samples/ninja_porsche.jpg

zuzzabuzz
12-22-2003, 12:27 AM
Doesn't Digital Confusion have trouble when anti-alias is set to Adaptive Sampling? Try changing that, see if that helps.

NanoGator
12-22-2003, 01:22 AM
I once did an experiment where I wanted to perform DoF *after* the initial render was done. (Post processing is one way to describe it.) What I did was I rendered out the image sequence as HDRI images. Then, I texture mapped those HDRI images using Front Projection on the objects (i.e. no lights or surfaces or anything, just the objects with the HDRI sequence texture mapped to them) and then I applied Digital Confusion. In *one* of the experiments I did, this wiped out a similar rendering error I had. I cannot say for certain that's what did it, but I thought I'd mention it at least once. At the very least, understanding what I did here could save ya some time down the road. Why spend 10 minutes rendering a scene to test a 30 second DC setting?

policarpo
12-22-2003, 04:17 PM
well the most efficient way of doing DOF effects is to render your scene in layers (foreground, midground, and background) and apply the blur in post.

Or, render out the depth map and use it to tweak your DOF in post (you may need to render it double size to avoid edge artifacts...or use the depth fog technique to generate a clean AA depth map for use in post).

this saves hours in the end. :)

post is king.

NanoGator
12-22-2003, 05:26 PM
The problem with post DoF is that Gaussian Blur isn't exactly what an out of focus lens does. For example, take Xmas lights on a tree. If you turn a lens out of of focus, those little specks become bigger and take the shape of the shutter. Apply a guassian blur to the same image in order to fake DoF, and you get a blob of pixels that aren't dependent on luminosity.

It really depends on the effect you're after, but that's one of the reasons I like Digital Confusion for all its faults.

policarpo
12-22-2003, 05:41 PM
yeah..it isn't a perfect solution by any means, but when you use this technique in combination with Lenscare...it's a near real time blast.

:)

http://www.frischluft.com/

NanoGator
12-22-2003, 06:00 PM
Thanks for pointing that out, I've been looking for a plugin like that!

Pity it's $175. I dun have the job yet! heh

FenrirWolf
01-06-2004, 10:51 PM
Hey, handy stuff! I've been experimenting with post-DOF. As NanoGator pointed out, it's not entirely perfect, but it's good enough in a pinch.

Dang, does DFX have anything like this? If it was just a filter I could plop down into my workflow, I'd be reaaaaally happy!

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