How 3D is Star Wars The Force Awakens?

This blog post looks at the 3D conversion process for The Force Awakens. Where it succeeds and where it falls short.

Last year I managed to blag tickets to the premiere of The Force Awakens - in 2D. The next day, we saw it again in 3D. I've never been a huge fan of 3D films and, despite owning a 3D TV, think the format is a bit of a gimmick.

But the 3D Star Wars was something else! Most of the scenes really didn't benefit - but some of the special effects just popped out of the screen.

The first thing to note is that SWTFA was not filmed with 3D cameras. The film was converted to 3D in post-production.

A few years ago I documented a process to convert 3D movies into animated GIFs. I'm going to use this technique to show you just how fake some of the 3D is.

Take a look at the famous opening crawl. This has been created entirely digitally - you can see the star field moving in parallax to the text.

When viewed through 3D glasses, this gives the impression of the text floating in front of the stars.

SWTFA successfully mixes live action and computer-generated special effects. In this shot, the actors have been filmed on a regular 2D camera and the "blaster shot" has been composited on afterwards.

As with much of the conversion, the frame is split into three distinct depths.

1. Popping out of the frame is the laser bolt.
2. In the middle we have Poe and the Stormtroopers.
3. Everything else is background.

Take a look at the troopers in the background - notice how they don't move in relation to each other - or the buildings behind them. If this were a true 3D scene, we'd expect to see some relative movement, but there is none.

Another sign of 3D conversion is the way lights reflect off a surface. Take a look at any normal reflective surface close to you. Wink your eyes alternately. Notice how the reflections on the surface jump around quite dramatically? Now look back at the foreground Stormtroopers. The reflections on their armour stay completely still.

I had naively thought that all the computer-generated special effects would have been rendered in 3D - but I'm not convinced that's true. Here we see some TIE fighters pursuing the Millennium Falcon.

Here, the 3D effect is noticeably worse! There is a fighter at the front of the screen - literally everything else is in the background. The position of the Falcon relative to the crashed Star Destroyer is static. The debris on the left of the screen should moving relative to the background, but it isn't.

In fact, looking at the TIE in the foreground - it looks like a 2D image floating above the rest of the scene. There's no discernible depth to it.

You can see this in some of the other shots. Here's Rey exploring the abandoned Star Destroyer.

The front floats above the background. Despite this being - I assume - an entirely CGI shot, it is little better than a South-Park-style paper-cut animation. Even worse, take a look at the right hand side of the image. A large blank gap where the image has just been squashed.

This happens constantly throughout the film. Here's what looks like an scene with huge depth - at first glance:

Look at both the left and right side. They've been artificially shunted inwards, leaving huge gaps!

That isn't to say there are some great 3D moments in the film. The character of Maz Kanata is entirely computer generated - and she looks amazing!

But, for every shot like that, you get this hot mess.

The angle of the sparks seem to change radically from foreground to background. The Lightsabre seems almost curved. There's no depth to the main character. And what the hell is happening on the right hand side? It looks like the picture has been squashed.

Thoughts

At first, I was disappointed with this conversion. This wasn't the fully immersive 3D world I'd been promised!

But then I remembered how much fun it was to watch the movie. After 5 minutes of a normal 3D flick the depth becomes about as entertaining as technicolor; it fades away. Or, even worse, it becomes a distraction as your eyes keep trying to catch up with what the brain thinks it is seeing.

But SWTFA keeps popping out of the screen without being obnoxious. Most of the action sequences have an exaggerated foreground object standing out from a flattened background.

There are a few notable exceptions - like the BB-8 shot at the top of this page and my personal favourite:

The hologram blurs as it exits the front of the picture. Finn's head seems to move beautifully behind the rest of the technical read-outs. This is one of the few shots which looks like it was filmed in 3D and also had 3D CGI applied.

And, yet, for all that - I still love the film. It's a fun romp and the 3D, while not perfect, certainly helps some of the scenes.

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Technical Notes

Here's how to create these animated gifs out of a 3D movie. These are mostly notes to myself!

ImageMagick can split an Over/Under movie into Left and Right images using:

mogrify -crop 100%x50% +repage 3D.png

For Side-by-Side you'll need to use:

mogrify -crop 50%x100% +repage 3D.png

This produces two files - 3D-0.png and 3D-1.png

You can, optionally, trim out the black borders with:

convert 3D-0.png -crop 1920x398+0+70 +repage 3D-0.png

(Substitute the correct resolution for your particular file.

Stretch the image back to full height using:

mogrify -resize 100%x200% 3D-0.png

You can make an animated GIF using:

convert +dither -delay 25x100 -loop 0 +repage 3D-0.png 3D-1.png 3D.gif

Or, you can make a movie using

avconv -r 1 -i 3D-%d.png 3D.ogv

This can be transcoded to webm and mp4 as needed