Anamorphic Screens Only Work From One Spot
The naked-eye 3D effect on corner LED screens is real, but it depends on one viewing point, and many of the clips that spread are visual effects.
The naked-eye 3D effect on corner LED screens is real, but it works from one viewing point. This guide explains how the illusion is made, why it breaks everywhere else and where the sweet spot falls on a stand, a stage or a building front. It also shows how to tell a VFX fake and gives a nine-point brief.
A sphere seems to roll out of a building corner. A wave seems to crash out of a box above the street. This naked-eye 3D is real, and it stops crowds. It is also fragile. An anamorphic LED screen works from one spot, and a designer has to plan around that spot.
How the anamorphic LED screen trick works
The content is designed for one viewing point, called the sweet spot, and mapped onto a large LED canvas. The canvas is often a corner screen, with two faces that meet at a right angle. Some are curved.
The content is built in 3D software. A virtual camera is placed where the real viewer will stand. The scene is then flattened onto the screen's true shape, as that camera sees it. Many designs draw the inside of a box, so the screen looks like a window into a deep room. Objects then seem to burst out of the box toward the street.
No glasses are involved. The depth comes from cues the eye already trusts, such as perspective, shadow and objects passing in front of one another. That is why people call it naked-eye 3D.
Why it breaks everywhere else
The image is correct for one eye in one place. Step to the side and the fold in the corner appears. The box bends. Objects that leapt out now look flat and stretched.
Distance changes how forgiving it is. Far from the screen, a step to the side barely changes your angle, so the zone where the trick works is wide. Close to the screen, the same step changes the angle a lot, so the zone shrinks to almost a point. A building front seen from across a square can hold a crowd in its sweet zone. A corner screen on a stand, seen from a few meters away, may hold one or two people.
Height matters too. The virtual camera sits at one eye height. Children, wheelchair users and people on a raised walkway all see a different picture.
Mark the sweet spot on the plan
Painters solved this long ago. In 1533 Hans Holbein painted a stretched skull across the floor of The Ambassadors. It only snaps into shape when you view it from the side. In Rome, Andrea Pozzo painted a false dome on a flat surface in the church of Sant'Ignazio. A marble disc in the floor shows visitors where to stand.
Do the same on the floor plan. Mark the sweet spot as a point with an eye height. Then draw the zone around it where the effect still holds, and check what is there.
- Stand. Where the sweet spot tends to fall: In the aisle, on the line out from the corner screen. What to check: It is not inside a neighbor's stand or the busiest part of the aisle.
- Stage. Where the sweet spot tends to fall: One seat, or the main camera. What to check: The rest of the audience sees a flat or bent image.
- Building front. Where the sweet spot tends to fall: Across a street or square. What to check: People can stop there safely, out of traffic.
On a stage, be honest about who the effect is for. Usually it is the camera. Render the content for the main camera, and tell the client that the room will see a bent image.
Design the approach
A sweet spot is useless if nobody reaches it. People walk toward a screen from many directions, and most of them see the broken version first. So design the walk.
Put a floor graphic on the spot, as Pozzo did with his disc. Leave room around it for people to stop, film and step away without blocking the aisle. Plan a short line if the stand expects one. Make the first view from the main approach look good even when bent, with strong color and motion rather than a depth trick that fails.
Then think about the loop. People who arrive mid-loop see a fragment. Keep the content short, so a person who waits at the spot sees the full effect soon.
How to tell a real effect from VFX
Clients arrive with clips. Many of the clips that spread are visual effects added to phone footage after the fact. They show things a real screen cannot do, and a client who expects them will be let down.
Run three checks before a clip goes into a brief. First, watch the camera. A real effect breaks when the camera moves off the spot. If the camera walks around and the 3D still holds, the clip is almost always VFX. Second, look for the place, the date and the screen owner, because real installations have all three. Third, look for footage from other angles. A real effect leaves bent versions all over social media.
A brief for anamorphic content
Send this with any request for anamorphic work.
- The screen's shape, including each face, the angle between faces and any curve.
- The resolution and pixel pitch of each face.
- The sweet spot, as a point on the plan with an eye height.
- The distance from the spot to the screen.
- Who the effect is for, whether visitors, one seat or the main camera.
- The approach routes, and what each one sees first.
- Daylight or show light on the screen, and the brightness needed.
- The loop length.
- A test on site, from the spot, before sign-off.
One spot, planned
Anamorphic content is a trick of geometry. Plan the spot as carefully as the content, and the trick works for the people you placed there.
Frequently asked questions
What is an anamorphic LED screen?
It is an LED screen, often a corner or curved one, showing content made to look three-dimensional from one viewing point. The content is rendered from a virtual camera at that point and flattened onto the screen's shape. From the right spot it looks deep. From anywhere else it looks bent.
Do you need glasses to see naked-eye 3D?
No. The effect uses depth cues the eye already reads, such as perspective, shadow and overlap. It even works with one eye closed. That is also its limit, because the image is only correct from the point it was made for.
How big is the sweet spot for an anamorphic display?
It depends on distance. Far from a large building front, the area where the illusion holds can be wide enough for a crowd. Close to a small screen on a stand, it can shrink to room for one or two people. Test from the spot before sign-off.
Can a stage use anamorphic content?
Yes, but usually for the camera, not the room. The content is rendered for the main camera, so viewers at home see the depth. The audience in the room sees a bent image. Tell the client early, and design content that still looks good flat.
The sweet spot is a point on a floor plan. Monet draws the stand or stage to scale on the venue plan and renders it in 3D in the real room, so the screen, the aisle and the place where viewers stop can be planned together.