The precheck is the first thing that happens when you start a new simulation. You describe your problem in plain language, upload your mesh, and the agent analyzes everything before you configure anything. It picks the solver, detects the fluid, classifies boundary patches, and fills in the full simulation setup for you to review.
What you provide
The precheck takes two inputs:
- Prompt, a free-form text description of your simulation. For example: "Simulate oil (SAE 30) flowing through a 2D pipe at 0.089 kg/s, outlet pressure 4 bar."
- Mesh file, a .msh file with your geometry. The agent reads patch names, cell count, and geometry to inform its suggestions. You can also pick from sample meshes (simple bend, S-curve, U-bend, complex network).
What the agent analyzes
The precheck runs four passes in sequence. You can follow the agent's reasoning in real time through the thinking steps that stream to the UI.
Boundary planning
The agent reads the mesh patch names and your prompt to classify each patch as inlet, outlet, wall, or symmetry. It also detects the flow regime (laminar vs. turbulent), time scheme (steady vs. transient), compressibility, and whether heat transfer or gravity matter.
Patch-level specification
For each patch in parallel, a dedicated agent generates the complete boundary condition: which BC type to use for each field (U, p, T, k, omega, nut), what values to set, and what assumptions it made. Each patch gets a confidence score.
Merge
All patch specs are consolidated into a single configuration object: physics settings, solver algorithm, fluid properties, turbulence model, and per-patch boundary conditions.
Review
A final pass validates the merged configuration for consistency. It checks that inlet flow matches outlet conditions, that velocity magnitudes are physically reasonable, that the turbulence model is suitable, and flags anything that looks wrong.
What it produces
At the end of the precheck, the agent returns a complete suggested configuration:
| Category | What it sets |
|---|---|
| Physics | Flow regime, time scheme, compressibility, heat transfer, gravity |
| Solver | Algorithm (SIMPLE/PIMPLE), max iterations, convergence criteria, time step, end time |
| Fluid | Preset selection or custom properties (density, viscosity, Cp, thermal conductivity, temperature) |
| Turbulence | Model (k-ω SST, k-ε, Spalart-Allmaras), intensity, length scale, hydraulic diameter, wall functions |
| Boundary conditions | Per-patch classification, per-field BC type and values, confidence scores |
Thinking steps
As the precheck runs, the agent streams its reasoning to the UI in real time. Each thinking step has a title and body text explaining what the agent is doing and why. This makes the analysis transparent so you can verify the agent's logic before accepting its suggestions.
Typical thinking steps include:
- Analyzing the mesh structure and patch names
- Identifying the flow regime from prompt keywords and Reynolds number hints
- Detecting the fluid type and looking up properties
- Selecting the solver based on compressibility and buoyancy
- Computing inlet velocity from mass flow rate and cross-section area
- Choosing turbulence model and estimating inlet turbulence values
Review checks
The final review pass produces individual check items, each with a status:
- OK, the check passed (e.g. "Inlet velocity 2.5 m/s is reasonable for pipe flow")
- Warning, something to be aware of but not blocking (e.g. "Mesh has only 5,000 cells, consider refining")
- Error, a problem that should be fixed before running
- Corrected, the agent found an inconsistency and already fixed it in the config
After the precheck
When the analysis is done, you click "Continue to simulation" to apply the suggested configuration. This takes you to the physics review step where you can adjust any setting the agent picked. Nothing is locked in; the precheck gives you a starting point, and you have full control to override anything before running.