How Does 3D Work?

Have you ever experienced a 3D film? They’re quite fascinating, aren’t they? Did you find yourself instinctively reaching out to interact with objects that appeared to be floating right in front of you?

3D stands for three-dimensional. “Normal” movies are 2D, or two-dimensional. What do dimensions mean and how do they differ?

Dimensions are attributes of space that refer to extension in a specific direction. For instance, two-dimensional (2D) images possess two dimensions: length and width. Imagine a picture drawn on a sheet of paper. The paper has length and width.

However, many things in the real world possess three dimensions. The third dimension is depth. Consider a cube. It not only has length and width, but it also has depth.

When you watch a movie, the screen is two-dimensional. It has length and width, but lacks depth. Therefore, “regular” 2D movies create the illusion that all the action is taking place on the big screen.

On the other hand, 3D movies introduce depth and immerse you in the experience. You witness cars racing towards you or snowflakes floating all around you. Isn’t modern technology incredible? But how do they achieve this?

Humans perceive depth and view the real world in three dimensions thanks to binocular vision. No, we don’t look through binoculars! However, we do have two eyes that are approximately three inches apart.

The separation between our eyes means that each eye perceives the world from a slightly different perspective. Our remarkable brains take these two slightly different images and perform the necessary calculations to create a sense of depth and enable us to judge distance.

Try these simple experiments to test your binocular vision. Extend one arm straight in front of you with your thumb pointing upwards. Close one eye and focus on your thumb. Now close the other eye. What do you observe? As you alternate between closing one eye and the other, you should notice your thumb appearing to shift slightly against the background.

Think binocular vision doesn’t make a significant difference? Grab a ball and ask a friend to throw it to you. Practice catching the ball a few times. Then, close one eye and attempt to catch the ball. Do you notice how much more difficult it is to judge distance and catch the ball?

Scientists have a technical term for the collaboration between your eyes and brain in perceiving three dimensions. It’s called stereoscopy. Stereoscopy is the concept that modern 3D technology seeks to replicate.

There are various types of 3D technology used today, but they all essentially achieve the same outcome. 3D movies and those amusing glasses work in conjunction to present each eye with different perspectives of the same image.

Depending on the specific technology employed, the 3D glasses you wear may utilize special shutters, color filters, or polarized lenses to receive the images. Your brain takes care of the rest!

For example, older (and some newer) 3D movies need to be viewed through special red and blue (or sometimes red and green) glasses. The images are projected in those colors — red and blue — and the special glasses ensure that each eye only receives one of the images. As always, your brain combines the images to create the 3D effect.

Modern movies utilize polarized glasses that exploit the fact that light can be polarized, or have different orientations. Modern 3D glasses with polarized lenses no longer require separate colors and can provide a much more realistic experience.

Your incredible brain automatically processes all of this 3D information. It’s an amazing machine! The most challenging aspect for 3D filmmakers is replicating this process with a camera, so that they can capture the correct images to be projected onto the movie screen and sent to your eyes.

In order to obtain a good 3D image, filmmakers must film two versions of the same image from the exact perspective as your eyes would see it. To achieve this, special film rigs are used, which consist of two cameras positioned to mimic the human eye’s viewpoint.

For animated 3D movies, animators essentially follow the same process. They create two versions of each individual frame to replicate the perspective of each eye. While it may be easier to obtain perfect images, it also requires a significant amount of extra time to create the additional frames.

Try It Out

Life would be dull if it were only in two dimensions, wouldn’t it? The third dimension adds so much excitement to everything! Enlist the help of a friend or family member and explore these enjoyable three-dimensional activities:

• Attempt to make your own 3D glasses! All you need is an old pair of glasses and this video to create your very own pair. Before you know it, you’ll be immersed in the action!
• Don’t just read about 3D movies, watch one! Borrow a 3D movie from your local library or rent one from a video store nearby. You may also be able to find one online or catch it on television. If you need 3D glasses, you can create your own. Simply refer to the activity below. What are your thoughts? Are 3D movies as amazing as you expected them to be? Why or why not?
• If you enjoy crafts, feel free to try out these entertaining 3D projects: + 3D Snowflakes + 3D Stars + 3D Bumblebees

FAQ

1. What is 3D technology?

3D technology refers to the creation or display of images and videos that appear to have depth perception, allowing the viewer to perceive them as three-dimensional objects rather than flat images. It is achieved by presenting each eye with a slightly different perspective, creating an illusion of depth and enhancing the overall viewing experience.

2. How does 3D work in movies?

In movies, 3D works by using a combination of stereoscopic filming and polarized glasses. Stereoscopic filming involves using two cameras placed side by side to capture two slightly different perspectives of the same scene. When these images are projected onto the screen, viewers wearing polarized glasses see different images with each eye, creating the illusion of depth and making objects appear to pop out of the screen.

3. What are the different types of 3D glasses?

There are several types of 3D glasses used in different 3D technologies. The most common ones are anaglyph glasses, which use red and cyan filters to separate the left and right eye images. Polarized glasses, on the other hand, use differently polarized lenses to filter out specific light wavelengths for each eye. Active shutter glasses work by alternating the images shown to each eye at a rapid rate, synchronized with the display.

4. How does 3D work in virtual reality?

In virtual reality (VR), 3D works by using a combination of specialized headsets and motion tracking systems. The VR headset contains two separate displays, one for each eye, which present slightly different perspectives to create the illusion of depth. The motion tracking system tracks the movement of the user’s head, allowing the perspective to change accordingly. This combination of visual and motion cues immerses the user in a realistic 3D virtual environment.

5. Are there any potential health risks associated with watching 3D content?

Extended exposure to 3D content can cause discomfort and fatigue for some individuals. These symptoms, known as “3D motion sickness” or “cybersickness,” may include headaches, nausea, dizziness, or eyestrain. However, the severity of these symptoms varies from person to person. It is recommended to take breaks and limit the duration of 3D viewing sessions to reduce the risk of experiencing these discomforts.