Film-Tech Forum ARCHIVE: 3D Question

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Posted by Andy Linde (Member # 5664) on 04-11-2010, 07:47 PM:

We use a Christie CP2000-M with Real D 3D and I've noticed that in some trailers and features there is a grayish vertical band (only visible through one eye) on either the left side of the screen. They vary in width depending on the shot. For example picture could be perfect in one shot, then the camera angle changes and there is a fairly large grey stripe on the left side only visible through the right eye. Sometimes you can see the stripes changing width during the shot too.

I found this really annoyed me while watching the Alice in Wonderland feature! So is it something to do with the way they make 3D films? Is it a Real D thing? Its as if the left and right eye images are slightly different aspects.

I didn't pick it up at all during Avatar, but definitely during Alice, and a few current trailers including Shrek the Fourth. [Confused]

Posted by Richard Fowler (Member # 893) on 04-12-2010, 07:36 AM:

Common on 3D that is generated from 2D source material....only so much to work with for layering and image shift.

Posted by Andy Linde (Member # 5664) on 04-12-2010, 08:55 AM:

But Alice was filmed specifically for 3D? You'll notice that the 'real life' part of the film before she falls down the rabbit hole is fine, but as soon as she falls in the stripes start appearing. Possibly happens with computer rendering? Although then you think you would notice it in films like Avatar which were largely computer modeled. Have been searching all over the internet for any other mentions of this but have returned no results. Would really love an explanation to put my mind at rest.

Posted by Pietro Clarici (Member # 4937) on 04-12-2010, 09:46 AM:

It's called "floating window", and it's intentional: http://digitalcinema.disney.com/dc3dFloatWinMov.aspx

Posted by Mike Blakesley (Member # 26) on 04-12-2010, 02:22 PM:

Alice was originally shot in 2-D and was "converted" to 3_D after filming but certain shots and elements were "planned" for 3-D. Whereas Titans was planned and shot as a 2-D film and was only converted to 3-D when the executives saw dollar signs.

Posted by Jonathan Althaus (Member # 5042) on 04-12-2010, 04:35 PM:

I've heard these referred to as "floating frames" and Disney is apparently huge on these. xmas carol and alice were very noticeable, but I didn't notice them in avatar or clash.

Posted by Andy Linde (Member # 5664) on 04-12-2010, 06:57 PM:

Yes, floating windows. It makes sense, and Disney IS huge on them! Honestly, they just distract me from the film [Frown]

Posted by Adrian Hauser (Member # 4723) on 06-09-2010, 06:31 PM:

Floating windows help with 3D Screen violations.
If part of the image is to be projected "infront" of the screen it only technically works if
that object is constrained within the screen edges. If it for some reason goes over the screen edge the 3D effect is broken. This can be marginally fixed by adding a floating window that perceptually moves the screen plane forward to the same convergence point of that object.
When finishing a film the last part is to do a pass where you try to direct where the eye will sit comfortably across cut points without having to make the viewer refocus each time on a new depth. This inherently means you have to violate some of the 3d rules and make Foreground objects break the screen edge. To fix these violations Floating Windows are incorporated to lessen the nauseating effect.

Adrian
Some more info on 3D post here.

www.iris-digital.org/wordpress