git:20260929.0a5602d to git:20261010.35e230a

# Design: 3d-acme

The spec `src/film.html` was built from. World units: y is up, the floor is y = 0; the frame is about 8.8 units tall at the camera's target.

## Canvas and loop

- 1080 x 1080, 60 fps, 10.000 s = 600 frames, cycle loop.

- Tempo 120 BPM: beat 0.5 s, 16th 0.125 s, bar 2 s.

- Live area 104 to 976 on both axes: the 3D type stays inside it at every sampled moment; the labels sit on the 8 px grid.

## Palette and materials

| Role | Hex | Used for | Material |

|---|---|---|---|

| bg | #221A3D | background and floor | floor shadow 0.42 |

| cream | #FFF1DE | the letters' faces | gloss 0.35 |

| coral | #FF6F61 | the letters' walls and bevels | |

| sun | #FFC53D | the ring (r 3.6, tube 0.13) | gloss 0.6 |

| teal | #35D0BA | three orbs (r 0.34) | gloss 0.7 |

| lilac | #9D8CFF | a rounded cube (0.8, radius 0.15) | gloss 0.4 |

Shading keeps hue: each surface is its colour times a light level, plus white highlights and rim.

## Light

Key light travelling (-0.38, -0.8, -0.9): from above, in front and to the right, strength 0.74; ambient 0.34; four filtered shadow taps, softness 1.3 texels on a 1024 px map over 18 units; rim 0.18.

## Camera

| At (s) | Yaw | Pitch | Distance | Target | Field of view | Spring |

|---|---|---|---|---|---|---|

| rest | -16 | 14 | 16.5 | 0, 0.35, 0 | 30 | |

| 1.00 | | | 15.0 | | | DOLLY |

| 7.00 | | | 16.5 | | | DOLLY |

Sway: 1 cycle per loop, 10 degrees of yaw.

## Objects

| Object | Kind and size | Rest place and turn | Colours | Motion | Loop |

|---|---|---|---|---|---|

| ACME | text, Unbounded 900, cap 1.08, depth 0.5, bevel 0.05, track +40 | 0, 0.02, 0 | cream / coral | 1.5: each letter turns over (rx -360, FLIP, 16ths); 5.0: hop 1.1 up (HOP, 16ths); 5.375: down (LAND, 16ths) | |

| RING | torus r 3.6, tube 0.13 | 0, 0.24, 0; tilted 4 and 3 degrees, just above the floor | sun | | orbit 1 (the tilt turns round, a slow wobble) |

| ORB | sphere r 0.34, 3 radial copies at r 4.3 | 0, 0.7, 0 | teal | | orbit -1, bob 4 x 0.3, phases spread |

| CUBE | box 0.8, radius 0.15 | 3.2, 0.4, -3.4; turned 30 | lilac | | spin 1 about y |

## Labels

| Label | Text | Face and size | Baseline | Colour |

|---|---|---|---|---|

| URL | EXAMPLE.COM | IBM Plex Mono 500, 40 px, +60 | 880 | sun |

| DEMO | DEMO COPY, FICTIONAL PRODUCT | IBM Plex Mono 500, 26 px, +20 | 944 | cream |

## Loop seam

- The flips end a whole turn from where they started and fold back to 0 once they settle; the hop returns to 0.

- The camera's dolly back (DOLLY, 5 s) is still settling at 10 s and carries over the seam.

- Cycles: ring orbit 1, orbs orbit -1 and bob 4, cube spin 1, camera sway 1.

## Formats

The same FILM renders at 9:16 and 16:9 (`--format`); `poster-9x16.png` and `poster-16x9.png` are frame 6.0 s of each.

- **9:16 (1080 x 1920).** The camera pulls back by itself so ACME keeps its width, and further (`contain: ['RING', 'ORB']`) so the ring and the orbs' orbit stay whole and centred through the loop; ACME's cap is about 84 px. The patch looks down more steeply (pitch 30) so the ring opens into a tall ellipse round the word, aims a little lower (target y -0.3) so the scene sits above the middle, lets the orbs bob higher (rest y 1.2, bob 0.8), and puts the labels under the ring (1272 and 1336).

- **16:9 (1920 x 1080).** The height frames it as at 1:1. The camera comes closer (dist 14, dolly to 13, target y 0.15), so the ring spans about two thirds of the width; the labels stay where they are.

- Stills critique at each format: 19 checks, all pass, the composition row included (the floor's shadows count as background). Loopcheck passes at each. A partial render of frames 0 to 119 at 9:16 verified (H.264, 1080 x 1920, BT.709, PSNR 41.6 dB and up) before the ring was contained.

## Checks

- The ring lies just above the floor so its near arc always passes below the word, never across it: a ring at mid-height sliced through the letters whenever its tilt turned toward the camera.

- Loopcheck: purity 0; the seam changes about as many pixels as any other 0.1 ms step (12,969 against 6,591 to 12,657).