A Tutorial in 3D

Just before we broke up for Christmas there was a 3D workshop and tutorial in aid of the 3D Story Telling Conference that will be commencing in January at Ravensbourne. This was designed to teach students about 3D and give them a taster of what they can help out with over the 2 day event. It is paramount that the students helping know the lingo incase of confrontation with some of the big players of the 3D word. We are going to be there to represent a professional University, it all needs to be as highly professional as possible.

As I am not a broadcasting student it was really interesting getting involved and learning about 3D technology. It is something I am still cynical about and have been for a while, but a really good opportunity to get all the facts and see what the world of 3D has in store for the future.

3D at present has just really hit off this year (2010) but it seems at the moment to still be a bit of a gimmick. What better way to sell tickets then to say its in 3D? Ticket prices are more expensive which means the films profit can become even greater. However some very terrible films dubbed “3D” that have not been shot in 3D and just been converted to 3D have terrible results. Clash of the Titans for example, a remake of a classic with 3D conversion. As someone quoted from Ravensbourne “3D doesn’t make a crap movie good.” Basically you can’t dress up sh*t. I think I can remember a quote from one of the actors from Clash of the Titans saying “I didn’t even know it was going to be in 3D,” indicating the last minute efforts to convert this abismal film, even though it scored in the top ten high grossing films of 2010, purely because of the 3D tag nether the less.

The Tutorial

A prediction has stated that by 2014 24% of households in the UK will have 3D television. This statement displays how very real 3D has become as far as our consumption of media is involved. At the moment 3D is new so its doing like what colour film did when it originally came out, the Technicolor phase of using colour really brightly and vibrantly, now its being used more subtly for story telling, this is basically whats going to happen to 3D, hopefully.

In 1838 Charles Wheatstone invented the stereoscope which was the birth of 3D. It became commercially viable when commercially viable cameras were available in 1947.

The birth of the first form of 3D was in 1922, where Anaglph Glasses were introduced, these are the classic 3D glasses of red and cyan. Creating 3D with analogue technology meant that the synching was not accurate enough. This lead to synching problems.

In the modern day digital cinema exists so 3D changed for the better to the technological trends. The adult film industry in the 1980’s adopted the 3D technology and fed into its development.

3D Fundamentals

Paralex – 2 eyes, 2 angles. The difference between the two images.

Interocular – The distance between the eyes

Converge – Our vision, our depth control. Humans have limited depth perception

Depth Budget – Distance between cameras and what you’re converged on

IA – Interaxial – Distance between the cameras. The more AI the more limited you are

Rigs

1) Side by Side  – better for colour matching but better for long shots, can’t get close to the subject

2) Beamsplitter – Good for close ups, more expensive. Uses two cameras at a 90 degree angle with a plate of glass at 45 degrees in the middle. The glass has a half coating of silver nitrate.

You can’t just pick one rig from another and use it for the whole film, you need to think about what you are shooting. The considerations you need to think about are:

  • Type of shot
  • Level of natural light
  • Weight of rig
  • Size of shooting space
  • Cost
  • Ease of use

The two ways to shoot 3D:

Parallel – Cameras that are identical, no issues with converged. No cross over of paralax i.e no left over right.

Converged – physically toe in of physical converged. Both the cameras cross over creating negative and positive spaces. The negative being infront of the screen and the positive being behind the screen. See Figure 1.


The images taken by each camera appears as a trapezium. As these shapes are not rectangular which we are used two, the two trapeziums and overlaid  to create a rectangle as you can see in Figure 2.

Stereoscopy

Stereoscopy is the process how 3D is created. It is similar to how we see but not the same. People have a very narrow focus. Our mental focus is very different to what we see in 3D films. 3D is designed to trick the brain.

Sky are known for having rules for the amount of percentage then have for image synching which is 3% (2% behind, 1% infront.) They have been known however to push this to 4.5%. The bigger the percentage though, the harder it is to synch and also can be dangerous to look at as it brings discomfort and irregular ways of seeing.

The Rig

We got to get a bit hands on with a 3D rig, it was already assembled but it gave us an idea of putting all this knowledge into context. It was for a anaglyph 3D build. We had to adjust the distances between cameras as well as from the object of focus. This proved a very tricky task and I could imagine how much more difficult it becomes to make a film if its in 3D.

The workshop got me rather excited for the 3D conference coming up in January, I need to compile a list of questions to ask some of the biggest names in the 3D world when they come to our University, the time is now!

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One Response to A Tutorial in 3D

  1. Great post dude. Really interesting run-down of what you learnt

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