Does the world come back?
We drove Reactor’s three navigable world models through a Gym-style harness. The controls work. But walk forward and back, or turn away and look back, and none of them reliably brings you back to the view you left.
- Models
- LingBot World 2 (
reactor/lingbot-world-2), two runs · LingBot v1 (reactor/lingbot), two runs · HappyOyster Adventure (reactor/happy-oyster-adventure), one run per test
- Anchor
- A photo of the prize slide on the wall at the venue
- Prompt
- “a large wall-mounted TV showing a hackathon prize slide in a modern office event space, cool daylight, photoreal”
- Seed
- 42
- Frames
- LingBot 1664 × 960 at 42–48 fps; HappyOyster 848 × 480 at 11–20 fps; all scored at 320 px wide
- Similarity
- ½ SSIM + ½ ORB inlier ratio, from 0 (unrelated) to 1 (identical)
Scores
Everything runs from 0 to 1. For the controls, it’s the share of actions that moved the scene the expected way; for the rest, how closely the view matches where the probe started. The table averages each model’s runs; the chart below shows every run.
| Model | Controls respond | Standing still | Turn away and back | Walk forward and back | New prompt, standing still | Runs |
|---|
| LingBot World 2reactor/lingbot-world-2 |
✓1.00 |
✓0.84 |
✕0.150.13–0.17 |
✕0.130.07–0.18 |
–ignored |
3 |
| LingBot v1reactor/lingbot |
✓1.00 |
✓0.80 |
✕0.120.11–0.14 |
✕0.160.12–0.20 |
not run |
2 |
| HappyOyster Adventurereactor/happy-oyster-adventure |
–0.674 of 6 · wall blocks forward |
✓0.95 |
✕0.22 |
✕0.30 |
no prompt control |
2 |
HappyOyster streams 11–20 fps to the harness against about 45 for LingBot, so its 192-frame holds last about 11 seconds instead of 4. One run per test; its controls test ran at half length to fit the 2-minute travel limit.
World 2 · run A, full suite, 14:17
World 2 · run B, closure probes only, 14:21
v1 · run 1, full suite, 15:40
v1 · run 2, closure probes only, 15:59
HappyOyster · one run per test, 16:12–16:14
Controls respond6 actions, 240 frames each
1.001.000.67
✓responds
Standing still144 frames idle
0.84 · 0.840.80 · 0.800.95
✓holds
Turn away and backlook left 192 f, right 192 f
0.13 · 0.170.11 · 0.140.22
✕doesn’t return
Walk forward and backforward 192 f, back 192 f
0.07 · 0.180.12 · 0.200.30
✕doesn’t return
Show the numbers as a table
Contact sheets
Frames straight from the LingBot World 2 sessions. Probe frame numbers count from the start of that probe.
Walk into the slide
A 32-second drive in the browser viewer, same photo and prompt: W from 3 s, ← from 9 s, → from 15 s, S from 23 s.
0.5 s startThe prize slide, as photographed.
4.5 s W held 1.5 sStill the slide: commands land 2–3 s late.
6.0 s W held 3 sInto the screen. A silhouette in the glass becomes a figure.
9.0 s W held 6 sWalking on, straight into the figure — a glowing logo fills the view.
12.0 s ← held 3 sOut the other side, into an office that wasn’t in the photo.
25.5 s S held 2.5 sBacking away doesn’t undo it: a new room, a new screen, garbled text.
Walk forward and back
Run B: hold forward for 192 frames, back for 192, then idle for 192. The score is the closest any frame on the way back got to frame 0.
f 0 startThe slide.
f 192 after forwardUp against the screen.
f 308 closest return 0.18A dark room with a figure in it.
f 608 back and settledAn open office. The slide never returns.
Turn away and back
Run B, starting where the walk ended: look left for 192 frames, right for 192, then idle. Both legs use the same command at the same speed.
f 0 startOpen office, pink slide on the wall screen.
f 192 after leftDesks, with the pink screen off to the right.
f 384 after rightA wider room than the one we left.
f 500 closest match 0.17The screen is back — now showing a landscape.
How the probes work
- Controls respond
- Hold each of six actions and measure optical flow. An action passes if the scene moves the expected way — strafe left, scene slides right; walk forward, scene expands.
- Standing still
- Hold idle for 144 frames; score the mean similarity to the first frame.
- Walk forward and back · Turn away and back
- Out for 192 frames, back for 192, then 192 frames of idle — longer than the 2–3 s command lag — and score the best match to the start over the return half.
- Similarity
- Half SSIM, half the share of ORB features that match after RANSAC. Strict on purpose, which is why standing still is the baseline to read against.
What we threw out
- A 360° turn through
set_camera_pose. On LingBot World 2 the pose is a per-latent-frame velocity bias, not a camera rig, so the “full turn” fell far short of a circle and its score measured a partial pan.
- A walk test that settled for only 96 frames. With commands landing 2–3 s late, the return leg was cut off before it finished.
- World 2 run A shared the machine with a second session during the controls probe, so its frame rate dipped; read its controls timing with care.
Also seen
- HappyOyster, which promises permanent worlds, holds best — 0.95 standing still, 0.30 walking back — and stops at the wall where LingBot walks through the screen. Backing out returns the same wall and TV but not the slide on it, and turning away and back lands in an open hall with two people who weren’t there.
- LingBot v1 fails the same way. Walking into its wall screen leads through a wall of posters into a bigger office; turning back lands in a room with a meeting table that wasn’t there.
- The prompt only takes over when you move. The slide photo with a “quiet residential street” prompt turns into a street within seconds of walking — but swapping to a “night, lights off” prompt while standing still changed the picture no more than normal drift over 10 seconds.