Viewing Results
Interpret factors of safety, critical surfaces, and analysis output.
Interpret factors of safety, critical surfaces, and analysis output.
After a search completes, JW Slope draws the results on the canvas and reports the governing factor of safety. The display controls in the Compute panel let you change which surfaces are shown, filter by analysis method, and adjust styling.
Critical surface
By default the canvas shows the critical slip surface — the trial surface with the lowest factor of safety — for the selected analysis method. The critical surface is controlled by the Show Critical Slip Surface toggle (on by default).
The governing result is printed in the results readout as:
Critical FOS = <value>A per-iteration breakdown ("Surfaces Per Iteration") lists how many surfaces were evaluated each iteration and the best factor of safety found.
Display controls
| Control | Default | Description |
|---|---|---|
| Show Critical Slip Surface | On | Draw the lowest-FS surface. |
| Show Slices | On | Overlay the slice subdivision on the critical surface. Available only while the critical surface is shown. |
| Show All Slip Surfaces | Off | Draw every trial surface, not just the critical one. |
| Hide Surfaces Outside Color Scale Range | Off | When showing all surfaces, hide those whose FS falls outside the color-scale min/max. Available only with Show All Slip Surfaces. |
Analysis method filter
The Analysis Type dropdown selects which method's results are displayed. It is populated from the methods that were actually computed (for example, Bishop Simplified, Janbu Simplified, Spencer, GLE / Morgenstern–Price). Switching it redraws the critical surface and readout for that method.
Surface styling
When many surfaces are shown, styling helps separate them visually.
| Parameter | Default | Min | Max | Description |
|---|---|---|---|---|
| Surface Thickness | 1 px | 0.5 | — | Line thickness of drawn surfaces. |
| Surface Opacity | 0.2 | 0.05 | 1 | Opacity of drawn surfaces. |
| Color Scale FOS Min | 0.8 | — | — | FS mapped to the low end of the color scale. |
| Color Scale FOS Max | 2.0 | — | — | FS mapped to the high end of the color scale. |
The color scale runs from warm (low FS) to cool (high FS); see the Factor of Safety Heatmap for the full color mapping.
Invalid surfaces
Trial surfaces that cannot be evaluated are excluded from the result and tallied by reason code in the readout, for example:
Invalid Surface Codes: required-slice-boundaries-exceed-slice-count (5), slice-material-coverage-gap (2)| Code | Meaning |
|---|---|
required-slice-boundaries-exceed-slice-count | The surface needs more slice boundaries than the slice count allows. Increase the number of slices. |
slice-material-coverage-gap | A slice base falls in a region with no defined material. Check that material regions tile the domain. |
Solver timings
The search progress modal reports per-phase timings (current value and running maximum, in milliseconds): candidate generation, surface generation, slice generation, LEM solve, bookkeeping, and total iteration time. Use these to see where search time is being spent.
LEM and FEM display modes
The result display has two tabs:
- LEM — the standard limit-equilibrium results described above.
- FEM — experimental finite-element outputs (groundwater and stress display).
FEM is experimental
The FEM tab surfaces experimental finite-element seepage and stress results. Treat anything shown there as experimental and not for production use.