JRunout Overview
Rockfall simulation and JWSplatt mass-runout modelling in the shared browser workspace.
All apps require a verified JWGeotech account and acceptance of the current Terms. Opening or reloading the app requires an internet connection to verify sign-in. An already authenticated tab can continue through temporary outages until its verified session expires; Browser and Native solving in JSlope and JRunout retain their licence requirements. Sign-out or session expiry locks the workspace and retains unsaved work in the tab. Signing in does not upload local project files.
Open JRunout to set up a project.
JRunout brings together rockfall simulation and JWSplatt mass-runout modelling. Both workflows include free Cloud solving during early access with a verified account.
The rockfall workflow supports individual rocks travelling across a terrain profile. It provides Lumped Mass and Rigid Body motion models, probabilistic rock and contact inputs, scenario batches, animated trajectories, stopping distributions, and runout graphs.
JRunout currently runs inside the same browser application and project
workspace as JSlope. The products share the CAD canvas, material catalog,
scenario explorer, and native .jws project file, but they are separate products
with separate Browser and Native licence permissions. Cloud solving and authoring are free during early access.
Use the Rockfall controls for independent rocks and the Runout controls for JWSplatt in the shared application.
For interacting failure masses, see the JWSplatt workflow.
Rockfall: what you can do
- Build collision terrain from the exposed surface of a closed 2D External Boundary.
- Assign Rockfall-specific restitution, friction, and roughness properties to terrain materials and individual surface segments.
- Define reusable Rock types by mass, density, shape, and appearance.
- Define reusable Rock Source types with rock populations, launch velocity, angular velocity, rotation, and probabilistic inputs.
- Place Rock Sources, projected Berms, Collectors, Barriers, and a runout Toe Point.
- Simulate all enabled scenarios with either the Lumped Mass or Rigid Body engine. Each rock is an independent, repeatable simulation job.
- Review all-rock or individual-rock trajectories, stop-density heatmaps, stopping distributions, solver progress diagnostics, histograms, and cumulative-frequency graphs.
- Export the displayed histogram or cumulative graph to CSV.
Product and runtime boundaries
| Boundary | Current behavior |
|---|---|
| Product and licence model | JRunout and JSlope are separate products with separate Browser and Native licence permissions. Cloud solving and authoring are free during early access. JRunout Browser and Native permissions cover both Rockfall and JWSplatt. |
| Browser runtime | Both products currently open in the same application shell. |
| Project | One .jws project can contain both Slope and Rockfall inputs. |
| Scenarios | Rockfall geometry and simulation settings vary by scenario. |
| Catalogs | Rock and Source definitions are project-wide; materials are shared with the project model. |
| Compute | Rockfall has its own compute command and runtime result cache. |
| Results on disk | Valid completed runs restore from .jws when they still match scenario inputs. Standalone .jwsr results can be exported but have no import command. |
Read the Cloud access and retention guide for processing, fair-use limits and downloads.
Important current limits
- Animated All Rocks and Individual Rock playback requires WebGPU. Static stopping distributions, heatmaps, graphs, and CSV export remain useful when WebGPU playback is unavailable.
- Rigid Body simulation uses the selected Rock shape. Lumped Mass simulation does not use the selected geometric shape.
- Collector and Barrier peak-impact records are reported in the Rockfall Graphs window with impact energy and Barrier retained/exceeded outcomes. The solver retains the highest-energy impact for each Rock/target pair; a separate CSV contains the full set of those retained peak records.
- Rocks, Stopped, Out of bounds, and Maximum runout remain in the solver window after a batch finishes. They are not copied into a separate results table or included in the distribution CSV files.
- Browser autosave preserves Rockfall inputs but not computed trajectories. To
preserve a valid completed run, save
.jws; otherwise run Rockfall again after a browser reload.