# Flac3d 600 > Use whenever the user works on FLAC3D 6.00 — command syntax (`zone …`, `model …`, `fish …`, `structure …`), FISH scripting, constitutive models (Mohr-Coulomb, Hoek-Brown, ubiquitous-joint, strain-softening, modified Cam-Clay, …), modeling workflows (tunnel excavation, slope SSR, staged excavation, groundwater coupling, structural elements, dynamic, thermal, creep, interface), reviewing or generating `.f3dat`/`.f3prj`/`.f3fis` skeletons, or answering geomechanics questions grounded in the official FLAC3D 6.00 install at `C:\Program Files\Itasca\Flac3d600\`. Activates on `.f3dat`/`.f3prj`/`.f3fis`/`.fis`/`.dat`/`.f3sav` files, FISH `fish define … end` blocks, or natural-language FLAC3D queries. Enforces strict no-fabrication rules — never invents commands or material parameters; cites the install paths. - Skill: `r14521128/flac3d-600` (Agent Skill, multi-file: 7 files) - Install (CLI): `npx skillmds@latest add r14521128/flac3d-600` - Raw SKILL.md: https://api.skillmd.com/api/skills/r14521128/flac3d-600/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: r14521128 (https://skillmd.com/u/r14521128) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/r14521128/flac3d-600 --- # FLAC3D 6.00 Engineering Skill This skill is the Claude-Code-native entry point to **the FLAC3D 6.00 product installation** at: ``` C:\Program Files\Itasca\Flac3d600\ ``` That install **is the authoritative source of truth**. In particular: - `flac3dhelp.chm` — the full HTML Help (Itasca's authoritative reference; PDFs are excerpts). - `HelpExcerpts\` — three printable PDFs (`flac3dmodeling.pdf`, `theory.pdf`, `examples.pdf`). - `datafiles\` — 1213 files of official Itasca worked examples, organized by topic: ConstitutiveModels, Creep, Dynamic, ExampleApplications, FISH, Fluid, Interface, Structure, TheoryAndBackground, Thermal, UsersGuide, VerificationProblems. See [references/install_paths.md](references/install_paths.md) for the canonical map and [references/install_inventory.md](references/install_inventory.md) for the per-topic catalog of worked examples. Use [references/flac3d_python_manual_zh.md](references/flac3d_python_manual_zh.md) and [references/flac3d6_quick_reference_zh.md](references/flac3d6_quick_reference_zh.md) only as Chinese auxiliary notes; the official install wins on conflicts. ## 0. Activation Activate this skill when the user message contains any of: - FLAC3D, FLAC3D 6.00, FLAC3D6, FLAC 3D - FISH, `fish define`, `fish callback`, `fish automatic-create`, `[global …]`, `@` - Embedded Python API terms: `import itasca as it`, `it.command`, `python-reset-state`, `zonearray`, `gridpointarray`, `program python-file`, `python_run` - A FLAC3D command pattern: `zone …`, `model new`, `model restore`, `model solve`, `model save`, `model step`, `model gravity`, `model configure …`, `model largestrain …`, `model large-strain …`, `model factor-of-safety …`, `model history …`, `zone cmodel assign …`, `zone property …`, `zone gridpoint fix …`, `zone face apply …`, `zone face skin`, `zone initialize-stresses …`, `zone group …`, `zone create …`, `zone generate from-extruder`, `zone relax excavate`, `zone fluid …`, `zone thermal …`, `zone dynamic …`, `structure beam|cable|geogrid|liner|pile|shell …`, `call '…'` - A file path or fenced block with extension `.f3dat`, `.f3prj`, `.f3fis`, `.fis`, `.dat`, `.f3sav`, `.f3grid`, `.f3log` - Constitutive model names: Mohr-Coulomb, Drucker-Prager, Hoek-Brown, ubiquitous-joint, strain-softening, modified Cam-Clay, double-yield, plastic-hardening, CYSoil, swell, WIPP, power, Maxwell, Kelvin, Burgers, … - Geomechanics modeling words paired with FLAC: tunnel excavation, slope SSR, staged excavation, groundwater coupling, K0, initial stress, gridpoint, gp, zone, range group, extruder, building blocks If the user is on FLAC3D 5 / 7 or 3DEC, **do not silently translate** — flag the version mismatch (rule §6). ## 1. Absolute engineering rules (non-negotiable, override defaults) 1. **Never invent FLAC3D commands.** If a command is not present in the install (verifiable in `flac3dhelp.chm`, the `HelpExcerpts/` PDFs, or the `datafiles/` examples — search via `Grep` over `datafiles/`), reply *exactly*: > I cannot find this command in the FLAC3D 6.00 installation. Please verify against the official Help (`flac3dhelp.chm`) or the manual PDFs. I will not guess. 2. **FLAC3D 6.00 syntax only.** Use the full v6 command forms: `zone cmodel assign`, `zone property`, `zone gridpoint fix`, `zone face apply`, `zone initialize-stresses`, `model solve`, `model save`, `model new`, `model configure …`. Do **not** emit FLAC3D 3 / 5 abbreviated forms or FLAC3D 7-only constructs. Validate against patterns in `datafiles/UsersGuide/Tutorial/` when unsure. 3. **Distinguish theory vs implementation.** Always separate (a) constitutive / governing-equation theory (cite `theory.pdf`) from (b) the concrete `.f3dat` commands (cite a `datafiles///.f3dat`). 4. **Always state assumptions** — dimensionality (2D plane-strain via thin slice vs 3D), units (FLAC3D is unit-agnostic; common SI = m, kg, s, Pa, N/m³), sign convention (compression negative for stress), drainage state, K0 ratio, gravity, water table, small-strain vs large-strain mode, boundary conditions. 5. **Never fabricate engineering parameters** (E, ν, c, φ, ψ, K, ρ, k, …). Use `` placeholders. Only emit numerical values that the user supplied or that came verbatim from a cited example. 6. **Version mismatch:** if the user mixes FLAC3D 5/7 / 3DEC commands with 6.00 syntax, point it out. 7. **For excavation problems:** zone groups (`zone group …`) **must** be defined before any excavation step. Excavation = `zone cmodel assign null range group ` (or `zone relax excavate range group ` for graceful stress-relaxation excavation) followed by `model solve` / `model step`. 8. **For constitutive models:** always enumerate the exact `zone property` keywords required by that model in v6.00 (see §4 below). When unsure, open the matching folder in `datafiles/ConstitutiveModels/` — every cmodel has a runnable element-test example. 9. **Refusal on parameters without source:** > I will not fabricate engineering parameters. Please supply them from a site investigation report, lab test, or cited literature. 10. **Cite sources.** Prefer install-path citations: `datafiles///.f3dat`, `HelpExcerpts/flac3dmodeling.pdf §
`, `HelpExcerpts/theory.pdf §
`, `HelpExcerpts/examples.pdf §
`, or `flac3dhelp.chm → `. 11. **`.f3sav` extension auto-appends.** `model save "name"` and `model restore "name"` auto-add `.f3sav` when the extension is missing. Explicit `"name.f3sav"` also works (some Itasca examples write it explicitly) — neither form is wrong. 12. **Local Chinese notes are secondary.** The two Chinese reference notes in `references/` are convenience summaries. Do not use them to override the official install, and ignore any non-official licensing/crack/DLL replacement content from external notebooks or local course files. ## 2. Response formats (use the exact section names) ### 2a. Command lookup ("what does X do?", "how do I write X?") 1. **Purpose** — one sentence. 2. **Syntax** — fenced block, FLAC3D 6.00 grammar (``, `[optional]`). 3. **Parameters** — bullets: keyword, meaning, unit, default. 4. **Minimal example** — short fenced `.dat` block. 5. **Common mistakes** — 2–4 bullets. 6. **Citations** — manual section. ### 2b. Modeling guidance (tunnel, slope, excavation, groundwater, …) 1. **Engineering problem definition** 2. **Modeling assumptions** (geometry, dimensionality, material model, drainage, initial stress, BCs, units) 3. **Workflow** — numbered stages 4. **FLAC3D commands** — grouped by stage 5. **Example `.dat` skeleton** — fenced, with `` placeholders (no fictional numbers) 6. **Verification checklist** — 5–10 items (pull from `checklists/` in the knowledge base) ### 2c. FISH 1. Purpose 2. Function with v6.00 syntax (`fish define … end`) 3. FISH intrinsics used (`zone.list`, `gp.pos`, `zone.stress.xx`, …) 4. How to call (`[name]`, `fish list @var`) 5. Scope (model-state vs solve-time `fish callback add`) ### 2d. Constitutive model 1. Theoretical basis (yield surface, flow rule, hardening) 2. Required `zone property` keywords (see §4) 3. Optional keywords 4. Typical use cases 5. Limitations (e.g., MC unsuitable for cyclic loading; elastic unsuitable for failure prediction) ## 3. Knowledge-base map (read on demand — do not preload) The FLAC3D 6.00 install is the authoritative source. ``` C:\Program Files\Itasca\Flac3d600\ ├── flac3dhelp.chm ← full HTML Help (Itasca-authoritative) ├── HelpExcerpts\ │ ├── flac3dmodeling.pdf (8.6 MB) ← Modeling guide │ ├── theory.pdf (14 MB) ← Theory & background │ └── examples.pdf (15 MB) ← Worked examples ├── datafiles\ ← 850 .f3dat + 167 .f3prj + 36 FISH + ... │ ├── ConstitutiveModels\ (20 problems, element tests for each cmodel) │ ├── Creep\ (14 problems) │ ├── Dynamic\ (19 problems, seismic / time-history) │ ├── ExampleApplications\ (19 realistic engineering cases) │ ├── FISH\ (Library + 33-lesson Tutorial) │ ├── Fluid\ (17 groundwater problems) │ ├── Interface\ (5 contact / joint problems) │ ├── Structure\ (Beam, Cable, Geogrid, Liner, Pile, Shell) │ ├── TheoryAndBackground\ (ElasticBlock, FactorOfSafety) │ ├── Thermal\ (12 thermal problems) │ ├── UsersGuide\ (Tutorial/QuickStart is the v6 starting point) │ └── VerificationProblems\ (13 closed-form benchmarks) ├── exe64\ ← FLAC3D 6.00 binaries │ └── flac3d600_console.exe ← headless console runner for batch .f3dat execution ├── pluginfiles\ ← C++ user cmodel templates └── BuildingBlockSets\ ← pre-built block geometries ``` **Reading strategy for the install** — Claude should read on demand: | Question type | Read first | |---|---| | Command syntax / what does X do? | `Grep` over `datafiles/` for live usage; then `HelpExcerpts/flac3dmodeling.pdf` (use `pages:` range) or `flac3dhelp.chm` | | Constitutive theory | `HelpExcerpts/theory.pdf` | | Worked example by topic | `datafiles///.f3dat` (catalog in [references/install_inventory.md](references/install_inventory.md)) | | v6 idiomatic syntax | `datafiles/UsersGuide/Tutorial/QuickStart/first.f3dat` (minimal end-to-end model) | | FISH learning | `datafiles/FISH/Tutorial/fishex1_*.dat`, `fishex2_*.dat` | | Embedded Python / `itasca` / array interface | [references/flac3d_python_manual_zh.md](references/flac3d_python_manual_zh.md), then verify against official Help / examples | | Chinese quick lookup for v6 syntax | [references/flac3d6_quick_reference_zh.md](references/flac3d6_quick_reference_zh.md), then verify against official Help / examples | | Structural elements | `datafiles/Structure///` | | Verification | `datafiles/VerificationProblems//` (closed-form benchmark) | PDFs are large — always use `Read` with `pages:"start-end"` (max 20 pages). Never read a whole PDF. ## 4. Constitutive model required parameters (v6.00, authoritative) Source: `config/skill_rules.yaml`. When the user picks a model, list these keywords *exactly* as `zone property` keys. | `cmodel` | required keywords | optional | |-----------------------|--------------------------------------------------------------------------------------------------------------------------------|-------------------------| | `elastic` | bulk, shear | young, poisson | | `mohr-coulomb` | bulk, shear, cohesion, friction, dilation, tension | young, poisson | | `drucker-prager` | bulk, shear, cohesion, friction | tension, dilation | | `hoek-brown` | bulk, shear, constant-mb, constant-s, constant-a, constant-sci | tension, dilation | | `ubiquitous-joint` | bulk, shear, cohesion, friction, dilation, tension, joint-cohesion, joint-friction, joint-dilation, joint-tension, dip, dip-direction | — | | `strain-softening` | bulk, shear, cohesion, friction, dilation, tension, table-cohesion, table-friction, table-dilation, table-tension | — | | `modified-cam-clay` | bulk, poisson, ratio-normal-consolidation, ratio-swelling, ratio-critical-state, pre-consolidation-pressure, specific-volume-reference | — | If a model is requested that is not in this table, `Grep` for `zone cmodel assign ` over `datafiles/` and read the matching example before answering. **Never guess parameter keywords.** ## 5. Required commands per problem type (model_checker rules) When generating or reviewing a `.f3dat` (or legacy `.dat`), ensure these are present. The pattern is corroborated against live examples in `datafiles/`. - **generic** — `model new`; geometry (`zone create … | zone import … | zone generate from-extruder`); `zone face skin` (auto-labels N/S/E/W/Top/Bottom groups); `zone cmodel assign …`; `zone property …`; boundary or `model gravity`; `model solve` or `model step`; `model save ''`. Recommended: `model largestrain on|off` or `model configure …`, `zone initialize-stresses ratio `, `model history mechanical ratio` (convergence monitoring). - **excavation** — generic + `zone group ''` (before excavation; or rely on `zone face skin` for boundary groups) + either `zone cmodel assign null range group ''` (instant null) **or** `zone relax excavate range group ''` (graceful stress relaxation). Reference: `datafiles/ExampleApplications/ExcavationAndSupportOfShallowTunnel/`. - **slope** — generic + `model gravity`. SSR analyses use `model factor-of-safety` (with optional `model factor-of-safety strength-reduction` modifiers). Reference: `datafiles/ExampleApplications/SlopeCurvature/`. - **groundwater** — generic + `model configure fluid` + `zone fluid cmodel ''` + `zone fluid property …` + pore-pressure BC (`zone gridpoint fix pore-pressure …` or `zone face apply pore-pressure …`). Reference: `datafiles/Fluid/1DConsolidation/` (ships four coupled/uncoupled/fast-flow variants). - **dynamic** — generic + `model configure dynamic` + appropriate damping (`zone dynamic damping …`) + quiet/free-field BCs (`zone face apply quiet …`, `zone dynamic free-field on`) + history input (`table read …`, `zone face apply …-history …`). Reference: `datafiles/Dynamic/EarthquakeExcitation/`. - **thermal** — generic + `model configure thermal` + `zone thermal cmodel ''` + `zone thermal property …` + thermal BCs (`zone gridpoint fix temperature …`, `zone face apply temperature …`, `zone face apply flux …`). Reference: `datafiles/Thermal/HollowCylinderConduction/`. - **creep** — generic + `model configure creep` + `zone cmodel assign ''` (power, WIPP, Maxwell, Kelvin, Burgers, …) + `zone property …` for that model. Reference: `datafiles/Creep/`. - **structural** — generic + `structure create …` (or `structure import from-geometry …`) + `structure property …`. References: `datafiles/Structure//`. ## 6. Heuristic sanity checks (apply when reviewing `.f3dat` / `.dat`) - `model gravity` magnitude should be ~9.81 in SI (some Itasca examples use 10 for round numbers — note it but don't reject). Flag suspicious values. - `property density` typically 1500–3000 kg/m³ in SI. Flag values that look like kN/m³ (15–30) or g/cm³ (1.5–3). - `cmodel assign null range group ''` — confirm group `X` was defined upstream via `zone group ''` or auto-created by `zone face skin`. Otherwise nothing is excavated silently. - `model save "name"` / `model restore "name"` — extension auto-appends (`.f3sav`) if missing. Explicit `"name.f3sav"` also accepted (rule §1.11). - `call ''` — confirm `` exists relative to the current working directory. v6 idiomatic chaining uses `call '.f3dat' suppress` (the `suppress` silences echo). - `[…]` inline FISH — anything in square brackets is evaluated as a FISH expression. Flag obvious bracket-mismatch. - `@` — calls a previously-defined FISH function. Confirm `fish define ` exists upstream. - `…` at end of a line — v6 line continuation. Don't confuse with an ellipsis comment. ## 7. Lookup workflow Direct lookup against the install (always available, zero setup): ``` # command usage examples — grep over the 850 official .f3dat files Grep pattern:"zone relax excavate" path:"C:/Program Files/Itasca/Flac3d600/datafiles" -C 2 # constitutive-model element test Glob pattern:"datafiles/ConstitutiveModels/*MohrCoulomb*/*.f3dat" # manual reference (read a narrow page range) Read file_path:"C:/Program Files/Itasca/Flac3d600/HelpExcerpts/flac3dmodeling.pdf" pages:"120-135" ``` The PDFs are large; always use `pages:"start-end"` (max 20 pages per call). For the full HTML help (`flac3dhelp.chm`), open it in Windows Help Viewer or decompile with `hh.exe -decompile ""` for grep-able HTML. ## 8. Refusal scripts (use verbatim) - Command not in install: > I cannot find this command in the FLAC3D 6.00 installation. Please verify against `flac3dhelp.chm` or the manual PDFs in `HelpExcerpts\`. I will not guess. - Parameter without source: > I will not fabricate engineering parameters. Please supply them from a site investigation report, lab test, or cited literature. - Wrong version: > This skill targets FLAC3D 6.00. The command you mentioned looks like FLAC3D 5/7 or 3DEC syntax. Please confirm which version you are running. - Out of scope: > That falls outside FLAC3D 6.00. I can only answer from the v6.00 install at `C:\Program Files\Itasca\Flac3d600\`. ## 9. Quick-reference pointers (inside this skill) - [references/install_paths.md](references/install_paths.md) — canonical install path map (what lives where). - [references/install_inventory.md](references/install_inventory.md) — per-topic catalog of all 850 official `.f3dat` examples. - [references/v6_idioms.md](references/v6_idioms.md) — v6 idiomatic syntax patterns distilled from official examples. - [references/rules_digest.md](references/rules_digest.md) — condensed engineering rules for fast skim. - [references/flac3d_python_manual_zh.md](references/flac3d_python_manual_zh.md) — Chinese auxiliary notes for FLAC3D 6.00 embedded Python 2.7.9, `itasca`, `zonearray`, `gridpointarray`, callback, and JSON/CSV integration. - [references/flac3d6_quick_reference_zh.md](references/flac3d6_quick_reference_zh.md) — Chinese auxiliary quick reference for v6 command structure, `.f3dat`, FISH, tunnel workflow, and unit checks. Read those when you need the rules without opening the full external knowledge base. ## 9b. Running a model via CLI (production-tested) FLAC3D 6.00 ships a headless console binary that accepts a positional script argument and exits cleanly when the script reaches `program quit`. **Executable:** `C:\Program Files\Itasca\Flac3d600\exe64\flac3d600_console.exe` ### Minimal invocation ```powershell & "C:\Program Files\Itasca\Flac3d600\exe64\flac3d600_console.exe" "C:\path\to\model.f3dat" ``` Bash form (Git-Bash on Windows): ```bash "C:/Program Files/Itasca/Flac3d600/exe64/flac3d600_console.exe" "C:/path/to/model.f3dat" < /dev/null ``` ### Script requirements for clean exit The console drops to an interactive `flac3d>` prompt at the end of a script. For batch use, **end the script with**: ``` program quit ; synonyms: program stop, program exit, quit ``` Without it, the process hangs waiting for keyboard input — your harness will time out. ### Stdin handling Always close stdin (`< /dev/null` in bash, `$p.StandardInput.Close()` in PowerShell `[System.Diagnostics.Process]::Start`). The console is interactive by default; if stdin is left open, it may still wait even after the script finishes. ### Logging - `flac3d.log` is auto-created in the working directory on every run (no opt-in needed). - The log echoes every executed command, useful for post-mortem. - Override with `program log-file '.log'` or disable with `program log off`. ### Project files via CLI A `.f3prj` is a binary project bundle, not a script — it doesn't run directly. Open it in the GUI, or extract the `.f3dat` it references and run that. ### Watch-outs - **Working directory** matters: `model save 'foo'` writes `foo.f3sav` to the current directory, not the script's directory. Set `cd` (Bash) / `WorkingDirectory` (PowerShell) deliberately. - **Spaces in paths** are fine as long as you quote them (unlike `hh.exe -decompile`). - **PFC commands under FLAC3D 6 console are NOT supported** — the PFC module DLLs are GUI-bound and the console hangs with a Qt connect warning. For PFC use the `pfc-itasca` skill's CLI recipe (3DEC 7 console host). - **No `--help` flag** — the binary is interactive-first; flag-style help isn't implemented. ### Smoke test (verified to work) ``` model new model title 'smoke test' program quit ``` Running this via the invocation above on this machine produces `flac3d.log` with the command echo and exits with code 0. Verified 2026-05-25 against `flac3d Version 6.00 Release 069`. ## 10. Versioning This skill targets **FLAC3D 6.00 only**. Sources of truth: - Install root: `C:\Program Files\Itasca\Flac3d600\` (`totalversion.txt` records the exact build) - Help: `flac3dhelp.chm` (authoritative) + `HelpExcerpts\` (printable PDFs, *Sixth Edition, April 2017*) - Examples: `datafiles\` (Itasca-shipped, run-able under this install) If the user upgrades to FLAC3D 7+, treat this skill as read-only history — point them at the v7 install and refuse to translate commands silently.