Add a geometric imperfection
add_imperfection_caseRead-only
Add a geometric imperfection — a global sway (out-of-plumb lean, EN 1993-1-1 §5.3.2) and/or a member bow — bound to specific load combinations. The solver perturbs the geometry before solving those combinations, so it feeds both first-order and P-Delta results. Give the sway as a ratio denominator (200 means a 1/200 lean); it is stored in radians. IMPORTANT: the engine ignores an unknown combination id SILENTLY, so a typo would apply no imperfection at all — this tool rejects unknown ids instead. Free.
Tool call template
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"load_combination_ids": "<load_combination_ids>"
},
"name": "add_imperfection_case"
}
}Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| model | No | Stringified FERS model JSON | |
| model_ref | No | Handle from stash_model, used INSTEAD of `model`. Avoids sending the whole document on every step; the tool returns the same handle back. | |
| sway_axis_x | No | Sway rotation axis X (default 0). | |
| sway_axis_y | No | Sway rotation axis Y (default 0). | |
| sway_axis_z | No | Sway rotation axis Z (default 1). The lean direction is axis x height_direction. | |
| height_direction_x | No | Direction height is measured along, X (default 0). | |
| height_direction_y | No | Y (default 1 — these models are Y-up). | |
| height_direction_z | No | Z (default 0). | |
| sway_magnitude_rad | No | Sway angle directly in radians, if you would rather not use a ratio (0.005 = 1/200). | |
| translation_axis_x | No | Bow direction X (default 1). | |
| translation_axis_y | No | Bow direction Y (default 0). | |
| translation_axis_z | No | Bow direction Z (default 0). | |
| load_combination_ids | Yes | JSON array of combination ids this imperfection applies to, e.g. [1,2]. Required — an imperfection only affects the combinations it names. | |
| translation_magnitude | No | Bow amplitude in model length units. Required when translation_memberset_ids is given. | |
| sway_ratio_denominator | No | Sway as 1/N: pass 200 for a 1/200 lean. Converted to radians for you. | |
| translation_memberset_ids | No | JSON array of member-set ids to give a bow imperfection, e.g. [1]. |