kirra-docs

Electronic Timing Constructs

Electronic Timing builds a temporal mesh: a triangulated surface in plan view where Z represents firing time in milliseconds, not ground elevation. You draw one or two timing contours (polylines or sampled Bézier curves), set timing parameters, then assign electronic detonators in the charging design so their fire times follow that surface.

This workflow is separate from connector timing (fromHoleID, timingDelayMilliseconds, visible arrows between collars). Electronic timing writes primer detonator fields for initiators marked Electronic in the charge design.

Availability: The Electronic Timing toolbar control is part of the experimental-electronics UI group. From v1.0.46, that group is shown automatically when loaded charging data includes at least one Electronic detonator on any hole (hasAnyElectronicCharging in kirra.js); it stays hidden when no electronic detonators are present. There is no separate global “enable experimental electronics” toggle. Visibility is refreshed when charging is loaded with the project.

Quick reference glossary

Term	Meaning
Timing construct	One complete temporal mesh: stored geometry, generated mesh, visibility, assigned holes, and parameters.
Timing contour	User-drawn polyline (or Bézier control structure); every vertex on that contour shares the same time at the ridge (relief mode) or lies on a fixed-time boundary (range mode).
Contour polyline	Connected chain of segments forming one continuous contour.
Contour vertex	Point where two segments meet; offset geometry uses interior vertex logic (bisector / mitre).
Relief	Rate of change of time with distance (ms/m). Treat it as a “velocity” of the timing wave along the offset direction, not acceleration.
Bisector	At an interior vertex, the direction used to place a single mitre offset point from the two adjacent segment normals.
Mitre join	One offset point along the bisector ray (normal case).
Mitre limit	Maximum mitre distance as a multiple of offset distance (implementation uses 3× the strip offset).
Mitre clamping	When the geometric mitre distance would exceed the limit, it is capped to avoid blow-outs and preserve vertex count.
Collapse	Adjacent offset vertices converge; strip generation stops for that direction.
Strip	One offset copy of the contour at a given perpendicular distance; assigned a single time value for that row of the mesh.
Quad strip	Corresponding points on two adjacent strips form quads, split into two triangles each.
Self-intersection	Offset polylines can fold back on themselves at large offsets or sharp corners.
Smooth temporal mesh	When enabled, the generator subdivides the triangulated temporal mesh (two midpoint passes) then applies Laplacian smoothing in X, Y, and Z (time). Smoothing strength is controlled by a numeric field (fractional passes supported, e.g. `1` = one full pass blend toward neighbours).
Bézier handle	Per-knot `cpIn` / `cpOut` control points; handles are collinear with independent lengths when editing.
Timing Relief tool	One contour plus explicit start time and relief (ms/m) → offset strips in both time directions.
Time Range tool	Two contours plus Line 1 and Line 2 times → stitched mesh; effective relief is derived between the boundaries.
Manual offset (`timeOffsetMs`)	Extra milliseconds added in the Electronic Timing dialog with + / − (per selected holes’ Electronic detonators). Cleared by Apply & Reset Offsets (on re-apply) or Reset Selected Hole Offsets.
Loading-stage offset (`offsetDelayMs`)	Set in Deck Builder for the detonator; always kept when you apply timing or reset manual offsets — it is not the same field as `timeOffsetMs`.

How it fits with charging and connectors

Charge the holes with at least one Electronic detonator on primers that should follow the mesh.
Create a timing construct and draw geometry (see below).
Assign holes to the construct (only assigned holes are considered when applying times).
Use Apply & Keep Offsets or Apply & Reset Offsets to re-sample times from the temporal surface at each assigned hole’s collar XY and write electronic detonator fields (including a link back to the construct id). See Apply timing and offsets below.

Connector-based hole-to-hole delays and electronic mesh times can coexist in one project; they address different initiation models.

Opening the Electronic Timing dialog

When the Blast Holes toolbar shows the control (see Availability above): toggle Electronic Timing. The dialog is a dockable FloatingDialog titled Electronic Timing (default size about 340×680 px).

Closing the dialog deactivates drawing mode and removes draw-complete listeners.

Dialog sections (what each control does)

Construct list

Dropdown — Select an existing construct or – Select – to clear the form.
New — Creates a construct with the current name (made unique if needed), tool mode, curve type, colour, and initial parameter fields.
Delete — Removes the construct from the project and database.

Name, colour, visibility

Name — Unique construct name; renaming runs when the field changes on an active selection.
Colour — Contour / display colour (#RRGGBB).
Temporal Mesh — Show or hide the shaded triangulated surface.
Contour Line — Show or hide contour polylines and direction cues drawn with the construct.

Tool and curve mode

Timing Relief — Single contour workflow; parameters are Start Time (ms) and Relief (ms/m) on the main parameter form.
Time Range — Two contours; Range Parameters expose Line 1 Time, Line 2 Time, and optional Extra Pts (Steiner-style density) per line.
Bezier — When checked, relief mode uses Bézier knots and handles; the mesh generator samples the curve to a polyline before strip offset.
Smooth — Enables post-processing on the generated mesh: triangle subdivision plus Laplacian smooth of vertex positions (including time as Z). Use the adjacent numeric field for smoothing strength (smoothPasses on the construct). Changing either triggers surface regeneration.

Edit on canvas (dialog open)

With the Electronic Timing dialog open (and the draw tool idle), hover and drag contour knots and Bézier handles in 2D or 3D. The ElectronicTimingEditTool uses capture-phase mouse events so drags do not start a canvas pan; C1 continuity is enforced when moving one side of a handle pair.

Drawing

Relief: Draw Polyline — Click vertices on the 2D canvas or 3D view; double-click or Enter finishes (minimum two points). Escape cancels.
Range: Draw Line 1 / Draw Line 2 — Same interaction; the mesh regenerates after both lines are complete.
Clear — Removes the relief polyline or both range lines, depending on mode.

While drawing, canvas panning is suspended (window.isElectronicTimingDrawActive).

Segments (Relief / sampled Bézier)

For each polyline segment between consecutive vertices:

Relief (ms/m) — Per-segment rate (the top-level Relief field can set all segments at once when changed).
Direction (°) — Bearing in degrees for the direction in which time increases (0° = North in Kirra’s bearing convention for this feature). Flip adds 180°.

Holes

Assign selected — Adds current selection to assignedHoles (combined id entityName:::holeID). Holes already on another construct are moved. Also runs interpolation immediately for feedback.
Remove selected / Clear all — Unassign holes from this construct only.
Apply Timing — Requires a generated surface; writes electronic detonator times for assigned holes and persists charging data to IndexedDB when available.

Offset (ms)

With holes selected, + / − adjust timeOffsetMs on Electronic detonators (step from the numeric field, default 5 ms). delayMs is updated from interpolated time plus offset. Charging data is saved when the database handle exists.

Time gradient

Colour stops define how time maps to colours on the canvas for construct visualisation (see getTimingGradientStops() export used by 2D/3D draw helpers). They do not change numerical firing times.

Surface

Regenerate — Re-runs surface generation from current geometry (useful after manual fixes or parameter tweaks).
Status text shows triangle and vertex counts when a surface exists.

Persistence

Constructs are stored in IndexedDB under the TIMING_CONSTRUCTS object store and held in memory in window.loadedTimingConstructs (a Map). See the wiki IndexedDB Schema for the store description.

KAP project files (v1.0.47+): Exporting a .kap (ZIP) includes timingConstructs.json — an array of [id, constructJSON] pairs. Importing a KAP restores constructs into memory and saves them back to IndexedDB (KAPParser.js / KAPWriter.js). Use KAP for full project round-trips that include electronic timing geometry.

Timing Sequences — Connector-based firing order, auto-timing, and validation.
Charging Overview — Deck builder and electronic initiators.
Harness Wire Assignment — SurfaceWire path/commander tool (separate from mesh timing).
Kirra wiki: Electronic Timing Constructs — Source file map and implementation notes.