Playback — run, seek, follow, and record a scenario

Everything you need to run a scenario sits in one row along the top of the LOGIC card. The run itself is executed by esmini compiled to WebAssembly, in your browser.

The transport row

Control	What it does
▶ / ❚❚	Starts or pauses the run. Shows a loading state while the runtime warms up.
⏮	Reset to start.
0.00s	Simulation time. Counts up during the run.
1x	Playback rate — 0.25x, 0.5x, 1x, 2x, 4x.
Follow: Off	Camera target — Off, or any entity in the scenario.
Ghost	Motion trails. Opens a popover with OFF, 0.25s, 0.5s, 1s, 2s, 5s.
PASS / FAIL / RUN / IDLE	The verdict badge. See End and fail conditions.

The card itself has two more controls: {x} opens the parameters and variables panel, and ˅ collapses the card to give the canvas the full screen. The top edge of the card is a resize handle (Resize Logic pane) — drag it up when the phase graph needs more room.

If there is no road, the transport row says so: No road — draw a road or import .xodr, with both phrases as links.

The timeline

Below the transport row is the timeline. Before the first run it shows Run ▶ to see the timeline.

Once a run has started it fills in:

• A block per actor, spanning the time that actor is doing something.
• A marker where each event starts.
• A playhead at the current simulation time.

Click or drag anywhere on the timeline to seek. Seeking is exact — every pose comes from the simulation, so the frame you land on has a defined state for every entity. That is what makes playback usable for review: pause on the exact moment of a cut-in and inspect the geometry instead of guessing while the run continues.

The ruler is not labelled with numbers, so read the time from the 0.00s readout after you seek.

Follow camera

Follow: Off is the default, and the camera stays where you left it. The dropdown lists Follow: Off plus one entry per entity — Follow: Ego, Follow: OverTaker, and so on.

Turn it on for anything longer than a screen. Imported road networks are often kilometres long; without a follow target the actors drive straight out of view within a few seconds and the run looks broken when it is not.

Ghost trails

Ghost stamps the actor’s outline onto the canvas at a fixed interval, leaving a visible motion trail behind it. Pick the interval from the popover: OFF, 0.25s, 0.5s, 1s, 2s, 5s.

Because the stamps are evenly spaced in time, their spacing on the canvas reads as speed — stamps bunching up mean braking, stamps spreading out mean acceleration. It is the fastest way to see a speed profile without reading numbers.

Ghosts also bake into image and SVG exports, so a figure you save for a slide shows the trajectory rather than a single frame. See Path and Footprint.

Verdict badge

Badge	Meaning
IDLE	Not running.
RUN	Running, no fail condition triggered yet.
PASS	Reached the end condition with no fail condition triggered.
FAIL	A fail condition triggered; the run stopped there.

When a fail condition triggers, the badge turns to a red FAIL and a matching × marker appears on the timeline at the moment it fired:

There is no button labelled “Run” — the ▶ button starts the scenario, and RUN is the badge that appears while it is going.

Recording a run

Hamburger menu → Export → Export video… records the run to a video file. The export runs in your browser, so nothing is uploaded. Aspect ratio and camera options are covered in Simulate an OpenSCENARIO file in the browser.

The rest of the Export submenu is useful next to it: OpenSCENARIO (.xosc)… for the scenario, .xodr (OpenDRIVE) for the road, image formats for figures, and Copy URL for a shareable link.

Exporting the scenario as .xosc

Export → OpenSCENARIO (.xosc)… (Scenario mode only) does not download straight away — it opens a small dialog first:

Field	Choices
VERSION	The OpenSCENARIO schema version — 1.0, 1.1, or 1.2 (default 1.1). 1.3 is shown but greyed out (“coming soon”), not yet selectable.
INCLUDE	.xosc on its own, or .xosc + .xodr together (the road plus the storyboard).
TARGET SIMULATOR	esmini or Generic. esmini tunes the output for the esmini runtime.
FILE NAME	The base name for the file(s).

Pick the version and bundling you need, then confirm to download. The .xodr (OpenDRIVE) item next to it, by contrast, writes the road immediately with no dialog (default name Untitled-<date>-<time>.xodr). For the full round-trip into esmini, see Export to OpenDRIVE / OpenSCENARIO / esmini.

Recording only part of the run

RANGE decides how much of the run reaches the file. It opens on Full — the whole run, exactly as before. Switch it to Trim to record a slice:

1. Open Export → Export video…, then click Trim.

2. Two handles appear on the seek bar, one per end of the range. What sits between them is what gets recorded; the rest of the bar dims.

   

3. Drag either handle along the bar, or type the seconds into Start [s] and End [s]. The dialog keeps the count under them — 5 s selected.

   

4. Click Start. The file lasts exactly as long as the range you picked.

The playhead stays live while the handles are up, so you can click inside the range and check a frame before you record it.

The range is deliberately not remembered: every time you open Export video… it starts at Full again. Aspect ratio, camera and ghost are a house style and do persist, but a range is tied to one scenario — every run has a different length, so last time’s seconds would land in the wrong place here.

If nothing moves

Symptom	Likely cause
The actor never moves	No event has triggered yet — check the trigger’s SECONDS, or that its phase’s Start condition is satisfied.
The actor drives, then stops for good	It reached the end of the road. Extend the road or import a longer .xodr.
The actor moves off-screen immediately	The follow camera is Off.
A Change Lane event fires but nothing moves sideways	TARGET is still Same lane with the actor referencing itself. See Actions.
Two events happen at once	Both triggers are still at 0.00 s.

See also

• End and fail conditions
• Open and play an existing .xosc
• Simulate an OpenSCENARIO file in the browser
• Path and Footprint