tosca

# Tosca .par File Authoring Complete reference for writing Tosca Structure parameter files (.par) that define optimization problems. Every .par file in this project is hand-written -- no API generates valid ones. ## When to Use This Skill **Triggers:** .par file, parameter file, design response, DRESP, objective function, OBJ_FUNC, optimization constraint, CONSTRAINT, Tosca parameters, OPT_PARAM, SIMP penalty, filter radius, sensitivity strategy, TOPO_SENSITIVITY, DV_TOPO, DVCON_TOPO, FEM_INPUT, SMOOTH block, SIG_SENS_MISES, volume fraction, material interpolation, MIMP, RAMP **USE for:** - Creating new .par files from scratch - Adding/modifying blocks in existing .par files - Debugging Tosca optimization failures caused by .par syntax - Understanding block dependencies and required fields - Configuring stress constraints, manufacturing constraints, or multi-load-case setups **Do NOT use for:** - Abaqus .inp file creation -> use `/abaqus-*` skills - Running Tosca from Python API -> Tosca uses CLI only - Post-processing ODB results -> use `/abaqus-odb` - Abaqus CAE topology optimization setup -> use `/abaqus-topology-optimization` ## Prerequisites 1. A valid Abaqus .inp file (the FEA model to optimize) 2. Element sets and node sets defined in the .inp file (referenced by GROUP_DEF or directly) 3. Full Abaqus license with Tosca module (not Learning Edition) 4. Understanding of the physical optimization goal ## What to Ask the User **Critical -- must know before writing any .par file:** 1. What is the optimization type? (topology, shape, bead, sizing) 2. What is the objective? (minimize volume, minimize compliance/strain energy, maximize frequency) 3. What constraints apply? (stress limit, displacement limit, volume fraction) 4. **What is the volume fraction target/limit?** Volume constraints are ALWAYS required — even when minimizing volume. Without a volume upper bound, the optimizer removes all material in one cycle. 5. What element groups define the design space vs. frozen regions? **With sensible defaults:** - Material interpolation: SIMP (default, good for compliance; use MIMP for stress) - Penalty factor: 3.0 (range 2-4; higher = sharper solid/void boundary) - Filter radius: 1.3 * avg element edge length (controls min member size) - Max iterations: 50 for compliance, 80 for stress-constrained - Move limit (DENSITY_MOVE): 0.25 for compliance, 0.10 for stress - Strategy: TOPO_SENSITIVITY (always for topology with constraints) - ISO_VALUE for SMOOTH: 0.3 (range 0.2-0.5) ## Block Dependency Order A valid .par file must define blocks in dependency order: ``` FEM_INPUT -> references the .inp file GROUP_DEF -> defines element/node groups (optional if sets exist in .inp) DV_TOPO -> references EL_GROUP (design space) DVCON_TOPO -> references EL_GROUP (frozen regions, manufacturing constraints) DRESP -> references EL_GROUP or ND_GROUP (what to measure) OBJ_FUNC -> references DRESP (what to optimize) CONSTRAINT -> references DRESP (limits on responses) OPTIMIZE -> ties DV, OBJ_FUNC, DVCON, CONSTRAINT together OPT_PARAM -> references OPTIMIZE (tuning knobs) STOP -> iteration limit and convergence criteria SMOOTH -> post-processing: isosurface extraction and STL export ``` ## Quick Reference See detailed documentation in `references/`: - `par-file-syntax.md` -- Complete block-by-block syntax reference - `design-responses.md` -- All DRESP types with usage rules - `common-patterns.md` -- Ready-to-use .par templates for 5 common setups - `troubleshooting.md` -- Error diagnosis, convergence fixes, common pitfalls ## Validation Checklist Before running Tosca with a .par file: | Check | How | |-------|-----| | Every block ends with `END_` | Search for missing terminators | | No line exceeds 160 characters | Tosca silently truncates long lines | | EL_GROUP names match .inp set names exactly | Case-sensitive match | | DRESP referenced in OBJ_FUNC/CONSTRAINT exists | Cross-reference ID_NAMEs | | OPTIMIZE references all DV, OBJ_FUNC, DVCON, CONSTRAINT | Nothing orphaned | | OPT_PARAM references the correct OPTIMIZE | Name must match | | .inp file path in FEM_INPUT is correct | Relative to Tosca working directory | | SIG_SENS_MISES DRESP excludes loaded/BC nodes | Prevents stress singularities | | For stress problems: ITER_MAX >= 75, DENSITY_MOVE <= 0.15 | Stress needs more iterations | ## Running Tosca ```bash # From the directory containing both .par and .inp files: "C:/SIMULIA/Commands/abaqus.bat" tosca --job <par_file_without_extension> 2>&1 # Example: "C:/SIMULIA/Commands/abaqus.bat" tosca --job Exp10_TO 2>&1 ``` ## Related Skills - `/abaqus-topology-optimization` -- Abaqus CAE side of topology optimization - `/abaqus-optimization` -- Abaqus Python API for optimization setup - `/abaqus-geometry` -- Creating the design space geometry - `/abaqus-mesh` -- Meshing for optimization (fine mesh, C3D8R or C3D10)