Film language 3D
About this app
Two figures in conversation, three film cameras and the line of action as a café scene in 3D. The camera images appear live as a film strip: if a camera stands across the axis, both figures look in the same direction across the cut. With shot sizes, a move across the axis and a neutral shot.
The line of action
Between two figures in conversation runs an imaginary line through both of them, the line of action or line of gaze. If every camera in the scene stays on the same side of that line, each figure keeps its side of the frame: in shot/reverse shot A looks right, B looks left, and their eyelines meet across the cut. If a camera jumps to the other side without a transition, the figures swap sides and appear to look in the same direction. Changing sides is still allowed: a visible camera move across the line or a neutral shot exactly on it brings the audience along.
What the app shows
A café scene in 3D with two figures, the line of action, the 180° zone, view cones and gaze arrows. Three film cameras stand in the room, and their images appear live as a film strip. The cut panel rates every transition as a match, an axis jump or a match via a neutral shot. For each camera you choose the shot size from extreme long shot to extreme close-up, the subject and the camera height; the focal length adjusts as you move the camera so the framing stays the same, shown as a full-frame equivalent.
Try it yourself
Start with the “shot/reverse shot” preset and play the cut. Then switch to “axis jump” and watch the film strip: both figures suddenly look the same way. The presets “move across the axis” and “neutral shot” show the two common ways to change sides cleanly. Drag a camera close to the line yourself and it snaps onto the axis. You can also move the figures or turn the pair by 90°; the line follows them while the cameras stay put.
Frequently asked questions
- What is the 180-degree rule in film?
- The 180-degree rule says that all cameras in a dialogue scene stay on the same side of the line of action, the imaginary line running through the two characters. Each character then keeps their side of the frame and the eyelines match across cuts. This keeps the audience oriented in the space.
- What does crossing the line mean?
- Crossing the line, or an axis jump, happens when the camera switches to the other side of the line of action between two shots without a transition. The characters swap sides of the frame and seem to look in the same direction in the reverse shot. Some films do this on purpose to create confusion or mark a break.
- How can you change sides of the line of action correctly?
- There are two common ways: a visible camera move across the line, so the audience follows the change, or a neutral shot exactly on the line, in which the character looks straight towards the camera. After such a transition the new side becomes the reference for the following shots.
- What can I try out in this app?
- You move three cameras and two figures in a 3D café scene and see the camera images live as a film strip. Four presets show shot/reverse shot, an axis jump, a move across the axis and a neutral shot. For each camera you set the shot size, subject and height, and the cut panel rates every transition.
Subject: Film & media
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