What is FlowGraph?
Kratos FlowGraph is a browser-based, node-graph editor for configuring KratosMultiphysics simulations. Instead of authoring a Kratos ProjectParameters.json by hand, you build the configuration visually: drop nodes onto a canvas, wire their inputs and outputs together, and FlowGraph generates the JSON that Kratos consumes.
Why a node editor?
A Kratos case is a tree of interdependent settings — an analysis stage references a solver, the solver references a linear solver, a time-stepping scheme, materials and a model part; processes reference variables and sub-model parts; outputs reference the model. Expressing those relationships as connections between nodes makes the structure visible and hard to get wrong:
- Each node corresponds to a concrete Kratos concept (a solver, a constitutive law, a process…).
- Connections express the "uses / is-configured-by" relationships between them.
- The generated JSON always reflects a valid wiring of those pieces.
What it is (and isn't) under the hood
FlowGraph is not a bundled single-page app. It is:
- a small Express + EJS server (
app.js) that serves a single canvas page and (optionally) launches Kratos, and - a large library of plain-ESM litegraph.js node definitions served statically from
public/js/nodes/.
There is no build step for the app. When the server renders the page it walks the node directory (src/module_importer.js) and injects every node file as a <script type="module">. Adding a .js file under public/js/nodes/ registers a new node — no manifest to edit.
Core capabilities
| Capability | Description |
|---|---|
| Visual editing | Add, move, connect and configure nodes on an infinite, zoomable canvas. |
| Node library | ~85 node types spanning analysis stages, solvers, materials/constitutive laws, processes, modelers, model parts and outputs. |
| Live JSON viewer | A side panel and a JSONView node show the generated JSON as you build. |
| Import | Reconstruct a full node graph from an existing ProjectParameters.json. |
| Export | Save/load the graph, export/import selections, or download a zipped, ready-to-run case. |
| Run (optional) | With a local Kratos install, launch the simulation directly from the backend. |
Continue to Installation to get it running, then walk through Getting Started.