Map V-patterns, deep char, soot shadows, and clean burn indicators on a room plan, then project fire spread vectors to estimate the most likely area of origin.
Pointer--, --
Estimated origin--, --
How to use this tool
Workflow
STEP 11
Load
Upload the scene plan
STEP 22
Pick clue
Click the burn mark
STEP 33
Drag vector
Aim fire travel
STEP 44
Read result
Check footer + export
Evidence legend
V-pattern Wall burn opens upward Deep char Area burned harder or longer Soot shadow Smoke blocked or redirected Clean burn Less soot from heat or airflow
Footer readout
VECTORS
How many evidence lines are active.
CONFIDENCE
How strongly the active vectors agree.
VARIANCE
How broad the origin area still is.
MODE
What the tool expects you to do next.
What you should do first
Load a clear plan, mark only patterns you can justify, and spread vectors across different surfaces instead of repeating the same clue.
What each evidence type means
V-pattern
A V-pattern is the familiar upward-and-outward burn shape often seen on a wall. It can suggest that heat and flames rose from a lower area, but it is not automatic proof of the exact origin.
Deep char
Deep char means a material appears more heavily burned, blackened, or consumed in one area than around it. It may indicate longer or more intense heating, but fuel type and material thickness matter a lot.
Soot shadow
A soot shadow is a protected or differently darkened area that suggests an object, surface, or airflow changed how soot was deposited. It can help reconstruct what was present or how smoke moved.
Clean burn
Clean burn is an area where soot seems lighter, removed, or absent because heat, ventilation, or direct flame exposure affected it differently. It is useful, but not every clean area marks the origin.
How to read the result
Use the footer as a quick health check for your mapping, not as a final forensic conclusion.
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Can burn patterns prove the exact point where a fire started?
No. Fire patterns can help generate and test origin hypotheses, but ventilation, suppression, fuel load, flashover, and post-fire disturbance can distort patterns. Real origin determination requires a systematic investigation.
Why do V-patterns matter in fire investigation?
V-patterns often reflect upward and outward flame spread on vertical surfaces. They can point toward a lower area of origin, but they must be compared with other evidence before drawing conclusions.
What does deep char indicate?
Deep char may indicate longer heating, greater heat flux, or fuel effects. It is useful context, but it is not automatically the origin because materials char at different rates.
Why use several vectors instead of one arrow?
A single pattern can be misleading. Multiple independent vectors reduce the influence of one damaged wall, one fuel package, or one ventilation path.
# Interactive Fire Origin Analysis from Burn Pattern Vectors
What this fire pattern origin analyzer teaches
Teaching simulator
This browser tool demonstrates how investigators reason from physical fire patterns toward a probable area of origin. Users map visible evidence, draw directional spread vectors, and watch the projected lines converge or disperse. The model is intentionally educational: it teaches geometry and pattern interpretation, not legal cause determination.
4 layersV-pattern, char, soot, clean burn
2D planstructural room map
3+ arrowsrecommended observations
0-100%confidence input
A disciplined workflow for fire pattern interpretation
Begin with safety, scene preservation, photographs, sketches, and systematic documentation before interpreting patterns.
Separate pattern types so V-shaped damage, char depth, soot deposition, and clean burn are not collapsed into one assumption.
Draw directional indicators only where the physical pattern supports a defensible direction of travel.
Look for convergence among independent observations rather than relying on the most dramatic damage.
Use the estimated area of origin as a hypothesis to test against fuels, ignition sources, ventilation, electrical evidence, and witness accounts.
Pattern
Potential value
Main caution
V-pattern
May suggest upward and outward flame travel from a lower area.
Can be altered by ventilation, flashover, wall geometry, and suppression.
Deep char
Can indicate sustained heat exposure or intense burning.
Fuel type and material thickness strongly affect char depth.
Soot shadow
May reveal protected areas, object placement, or airflow effects.
Moved furniture or suppression activity can change the interpretation.
Clean burn
Can show high heat, ventilation, or late-stage burning.
It does not automatically identify the first item ignited.
Better origin hypotheses
The best hypotheses explain multiple observations at the same time.
Independent vectors converge
Evidence fits known ventilation paths
Fuel packages are accounted for
Alternative origins are actively tested
Weak origin hypotheses
Weak hypotheses often rely on one pattern without testing distortion factors.
One dramatic char area is treated as proof
Flashover is ignored
Suppression damage is not documented
Ignition source evidence is assumed
# How the Vector Model Works
Each arrow is treated as a projected line of fire travel. The estimator calculates pairwise line intersections, filters points that fall within a reasonable plan boundary, averages the remaining crossings, and reports a radius based on the spread of those intersections. A small radius with several vectors produces a stronger convergence signal. The intersection model works by solving the parametric equations of two lines extending from their respective evidence markers. When two vectors point toward a shared region, their theoretical crossing point contributes one coordinate to the averaging pool. The more independent vectors that participate, the more the estimator can filter out crossings that sit far from the main cluster, effectively reducing the influence of any single observation that might be poorly oriented or misinterpreted.This geometric approach mirrors a classroom sketching exercise: it helps students see why origin analysis improves when observations come from different surfaces and pattern types. It also exposes a common problem: arrows can intersect even when the underlying interpretation is poor, so the mathematical center must never replace fire science judgment. In a real investigation, practitioners compare the plotted result against ventilation paths, fuel load distribution, structural damage, and witness statements before treating any coordinate as a likely origin. The tool encourages this habit by displaying variance alongside the estimated point, reminding users that a tight cluster of crossings is only as strong as the quality of the observations that produced it.Beyond the basic intersection logic, the estimator applies a boundary constraint so that crossings located far outside the room plan are excluded. This prevents outliers from dragging the averaged center toward impossible locations. The final radius represents the standard deviation of the remaining crossing coordinates, giving a direct measure of how consistently the active vectors agree. A radius under ten percent of the plan span indicates strong convergence. A radius exceeding a quarter of the plan signals that the evidence does not yet support a focused origin, and more or better observations are needed before drawing conclusions.
Area of origin
The general region where available evidence suggests the fire began.
V-pattern
A fire pattern that often appears as upward and outward damage on a vertical surface.
Clean burn
A lighter or cleaner area caused when soot is burned away or not deposited under high heat or airflow conditions.
Soot shadow
A protected or differently deposited soot area that can preserve information about objects, airflow, or heat exposure.
Vector convergence
The clustering of projected directional indicators around a common region.
Do not turn convergence into certainty
Forensic caution
A tight intersection cluster is useful only when the observations are valid. Real investigations must account for ventilation, flashover, fuel packages, electrical systems, appliance evidence, witness statements, suppression, and scene disturbance.