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3DS Max Z-Depth

Posted: Mon, 12th Apr 2010, 5:11pm

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nuyawk

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Hi All - I searched through the forum but didn't find anything "Z-depth" related as it applies to 3DS Max.

Would anyone know of a method/technique to achieve this? I've fooled around with it a bit but can't get it to work.

It's basically rendering out two passes in order to give a regular 2d image depth of field... wait, here's a youtube video that shows it being done in Combustion, he says it can be done with any compositing software but I'm not seeing it.

http://www.youtube.com/watch?v=ViVgs4Q17EQ

Any help would be greatly appreciated, I'm up to my elbows in renders and animations and this just might push me over the edge! sad
Posted: Mon, 12th Apr 2010, 6:49pm

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Axeman

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CompositeLab doesn't work with Z-depth as such, unfortunately.

However, here's something you could try in order to get a similar effect:

Add both of your renders to the Clab timeline, with the Z-depth render below the other one. Now, add a Grade Object above everything, add a blur to it, and then add an Object Mask, using the info from the Z-depth pass as the source for the Object Mask. If the Z-depth pass doesn't include an actual alpha channel, you can select the RGB info from that layer as the source for the Object Mask. That might work.
Posted: Mon, 12th Apr 2010, 10:48pm

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nuyawk

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Hmmm this is looking promising... I guess Axeman knows a thing or two about this software huh? smile

The only issue now is the z-depth channel is leaving a white ring around the object in the foreground... I will try something with it but it's looking kind of jagged (like something to do with anti-aliasing, maybe)

Any ideas feel free to share, in the meantime I will continuing tweaking and see if anything comes of it.

Thanks!
Posted: Mon, 12th Apr 2010, 11:16pm

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Axeman

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It worked, then? To some extent anyway? Awesome. I've never tried this personally, I was just brainstorming, so I'm glad to hear the concept actually works anyway.

The z-depth pass is a greyscale image, correct? If so, then applying a grade filter to that layer and adjusting the contrast could help tighten the edges for you. A contrast filter or Levels might do the trick. I'd probably try Levels or Contrast Pro to see if that works. Since the greyscale serves as the source for the Object mask, adjusting the greyscale will adjust the mask as a result. Assuming I understand correctly what the issue is. If you don't figure anything out, could you perhaps link to an image or clip showing the white ring you mention?
Posted: Tue, 13th Apr 2010, 12:08am

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nuyawk

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Not 100%... there is SOME blur but when I crank up the gaussian (on the Grade Object added at the top) it doesn't want to create more blur.. strange

I always test using spheres since it would take too long to render actual scenes, especially when testing. Here is a link to how the three sheres look with the slight blur and the rings around them... the rings are caused by the z Depth layer with the actual circles being white and the background black.

http://www.2931studios.com/ballstest.htm

I tried inverting the Z depth layer but nada... it will take a lot of tweaking to find out if/how it works. Maybe it's even something I'm doing with the Z Depth layer, up until now I've just rendered in layers (Foreground/background) and created my DOF there.

Thanks!
Posted: Tue, 13th Apr 2010, 12:16am

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Axeman

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Rating: +1

On the Z-depth pass, white is foreground (in focus) and black is background (completely blurred), correct? With the various shades of grey falling in between?

I'm not seeing how the grade object could introduce new color data to the clip, if all it includes is a mask and a blur. Is your project set up like this:

Layer 3: Grade Object [Visibility: ON]
Object Mask (Source: Layer 1)
Layer 2: RGB Render Pass [Visibility: ON]
Layer 1: Z-depth Pass [Visibility: OFF]

this is how I picture it being set up, and how I would handle it. I don't see how, if those white circles aren't in Layer 2, that Layer 3 could create them. Also, using nearly any shape other than spheres would help to show what the dof is doing; a perfectly smooth, even surface, without any texture or edges, makes it hard for any blur to register.
Posted: Tue, 13th Apr 2010, 1:13am

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nuyawk

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You son of a sailor...


have a look: http://www.2931studios.com/zdepthtest2.htm
the image on the left is the original, the one on the right is adding the layers etc.

Looks like now FXHome can put "works with 3DS Max ZDepth!" in the advertisements.

Of course I will do more research and use something other than teapots and let you guys know how it looks.

And for anyone doing a search on using the 3ds max 'Z Depth' render element with VL just follow Axeman's instructions above (the instructions he gave off the top of his head which is f'n scary!) smile

Thanks man, off to do some rendering!
Posted: Tue, 13th Apr 2010, 9:40am

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Simon K Jones

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Very cool!
Posted: Thu, 3rd Jun 2010, 7:56am

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FXhomer145050

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Hi, I use Cinema4D and the Zdepth trick donĀ“t give good results (at least for me), would be nice to have some kind of lens blur, where you can put zdepth layer and control the amount of blur and a invert button would be nice too.

Cheers
JC

Playing still with the demo smile