Stand in the middle of a straight road or a long hallway and look ahead. The sides seem to come together far away. In a drawing, that meeting place is the vanishing point, and it sits on the horizon line.
When you face a box straight on, its front is a flat rectangle: its horizontal edges stay horizontal, and its vertical edges stay vertical. Only the edges that go back, away from you, slant. All of them aim at the same single point. This is one-point perspective.
Drag the vanishing point (the pink dot) or the horizon line and watch the boxes change.
🔑 Key idea
In one-point perspective, every edge that goes straight back from you meets at one vanishing point on the horizon line. Edges across and up and down stay horizontal and vertical.
💡 Why it works
Parallel lines going away from you never meet in real life, but the space between them takes up a smaller and smaller angle of your view as they go farther. Far enough away, the gap shrinks to nothing: that is the vanishing point. Lines that go straight away from you all shrink toward the point straight ahead of your eyes, which is on the horizon line.
✏️ Worked example: Draw a box
How do you draw a box in one-point perspective?
Draw the horizon line and put one vanishing point on it.
Draw the front of the box as a plain rectangle.
From each corner, draw a light line toward the vanishing point.
Decide how deep the box is and draw the back edges parallel to the front edges.
Erase the extra parts of the guide lines.
Answer: A box whose back edges all aim at one point.
Practice: draw boxes above, below and across the horizon line. You can print the sheet.
⚠️ Common mistake
Two common slips: edges that go back but miss the vanishing point (the box looks twisted), and a vanishing point placed above or below the horizon line. Check with a ruler: extend each back edge. All of them should cross at one point, and that point should sit on the horizon line.
Leonardo da Vinci used one-point perspective in The Last Supper: the lines of the ceiling and the side walls lead back toward a point at the head of the central figure.
The Last Supper. Look for the lines of the ceiling and walls and follow them back.
Practice
Pass with 3 right answers, the last 2 in a row. Each right answer earns 2 XP.