Four UV maps on one square
From the left: the whole picture, the right half, v flipped (the F upside down), and no uv attribute (one flat colour).
UV coordinates say where each vertex sits on a picture, so a flat image can wrap a 3D shape. Bounding boxes and spheres say how big and where a shape is, so you can centre it, fit the camera to it and let three.js skip it when it is off screen.
Change the code and press Run (Ctrl+Enter). Predict what will happen first, then break it on purpose and read what changes. Your edits are saved and match the lesson page.
Ready for more? This phase has 4 hands-on exercises with automatic checks.
Practice questions
Write the code in the editor, run it, then open the model answer to compare.
Make a UV set that tiles the picture 3 times across a square. Which numbers go in, and what must the texture's wrap mode be?
Write a function placeOnFloor(mesh) that moves a mesh so its lowest world point is at y = 0.
Explain it without notes
What are u and v, and what happens if a geometry has no uv attribute?
How would you put a loaded model's feet on the floor and its middle on the centre line?
Console
Nothing logged yet.Expected console output
whole picture uv: 0 0 1 0 1 1 0 1
right half only uv: 0.5 0 1 0 1 1 0.5 1
upside down (v flipped) uv: 0 1 1 1 1 0 0 0
no uv attribute uv: none