Flotherm Sim

sim connect --solver flotherm --ui-mode gui     # launch Flotherm GUI (needs RDP/interactive desktop)
sim exec '<path>.pack'                          # import pack into GUI
sim exec 'solve'                                # run CFD solve
sim exec 'status'                               # query session state
sim disconnect                                  # kill all processes

Requirements: sim serve must run in an interactive desktop session (RDP, not SSH session 0). The GUI binary needs a real desktop to render Qt widgets.

Direct batch — headless optimization for re-solves only

Bypasses floserv — calls translator and solver executables directly. Works from SSH with no interactive desktop, BUT only for projects that already exist in FLOUSERDIR (i.e., previously imported/created via the GUI path).

call flotherm.bat -env                              :: set environment only
translator.exe -p "<FLOUSERDIR>\<project>.<GUID>" -n1   :: discretize model → msp_0
solexe.exe -p "<FLOUSERDIR>\<project>.<GUID>"           :: run CFD solver

What this path can do:

• Re-solve an existing project with no parameter changes (e.g., crash recovery, rerun with different iteration count after manually editing solver_control)
• Run on a Flotherm project that was originally imported via the GUI path
• Fully headless, fully scriptable, works from SSH

What this path cannot do:

• Create a new project from scratch
• Import a .pack file (needs GUI automation)
• Modify model parameters (requires FloSCRIPT playback, which is broken in CLI)
• Change geometry, materials, boundary conditions, power values, etc.

Solver log: <project>/DataSets/BaseSolution/PDTemp/logit
Result fields: <project>/DataSets/BaseSolution/msp_*/end/Temperature etc.
Solver variants: solexe.exe (single), solexed.exe (double), solexe_p.exe (parallel)

Decision rule

• Need to import a .pack or create/modify a project? → GUI automation
• Just re-solving an existing unmodified project? → Direct batch (faster, headless)
• Need model parameter modification headlessly? → Not yet possible (see known_issues.md ISSUE-003)

How GUI automation works

sim exec → driver.run() → _play_floscript(script_path)
  ├─ subprocess: pywinauto UIA expand() Macro → invoke() Play FloSCRIPT
  │  (invoke blocks due to modal dialog; subprocess killed after timeout)
  └─ main process: Win32 ctypes fills file dialog → clicks Open

UIA runs in a subprocess to isolate COM state corruption from the server process. The file dialog is a standard Windows dialog, handled via GetDlgItem(1148) + SendMessage(WM_SETTEXT) + BM_CLICK.

base/ — always relevant

solver/<active_solver_layer>/ — release specifics

Empty stubs by default; per-release deltas land here as discovered.

• solver/2504/notes.md — 2025.1, current
• solver/2412/notes.md — 2024.4
• solver/2406/notes.md — 2024.2

known_issues.md and tests/ (top-level)

Top-level QA artifacts. known_issues.md documents the vendor-defect-broken headless batch mode. tests/ is the pytest suite for the inline driver. Not loaded during a normal session.

Example files (reference only)

This skill's workflow scripts and skill_tests/ reference vendor-shipped demo models by the paths where they live inside a local Flotherm install. The sim-skills repo does not bundle any of that content (it is proprietary Siemens / Mentor Graphics material and was removed under issue #2 for IP compliance). To reproduce the tests, point the helpers at your own Flotherm 2504 install — default on Windows is C:\Program Files\Siemens\SimcenterFlotherm\2504\examples\ (override in flotherm/tests/execution/run_helpers.ps1 if installed elsewhere).

For Flotherm 2410, the same subpaths apply under C:\Program Files\Siemens\SimcenterFlotherm\2410\examples\.

Model generation (building from scratch)

To build a Flotherm model from a natural language description, generate FloSCRIPT XML step by step. See base/reference/floscript_modeling.md for the full command reference, common patterns, and pitfalls.

sim connect --solver flotherm --ui-mode gui
sim lint step1.xml                          # XSD validates automatically
sim exec step1.xml                          # create geometry + save checkpoint
sim lint step2.xml
sim exec step2.xml                          # add sources + save checkpoint
sim exec 'solve'                            # run CFD
sim disconnect

Each step is a separate FloSCRIPT file with <project_save_as> at the end for crash recovery. Lint before play — XSD validation catches typos and structural errors with line numbers.

Hard constraints

1. GUI must be visible. The automation uses pywinauto UIA which requires the Flotherm window to be in an interactive desktop session. sim serve must be started from RDP, not SSH.
2. Don't open Flotherm by hand while sim is using it. UIA element discovery races with user input. Let the driver own the lifecycle.
3. UIA must run in a subprocess. invoke() on Qt menu items throws COMError and corrupts COM state for the entire process. Always isolate in subprocess.Popen with timeout.
4. Acceptance ≠ exit code. Always extract a numeric (max temp, junction-to-ambient ΔT) from the .pack output and validate against the user's criterion.

Required protocol

1. sim connect --solver flotherm --ui-mode gui — launches Flotherm
2. sim exec '<path>.pack' — imports pack (uses project_import FloSCRIPT with import_type="Pack File")
3. sim exec 'solve' — plays <start start_type="solver"/> FloSCRIPT
4. Verify solve completed: check Message Window for I/9001 - Solver stopped: steady solution converged
5. sim disconnect — kills floserv, floview, flotherm