Parametric Analysis

Parametric Analysis moves part of the External Boundary in steps and adds one scenario group per step, as the Section Wizard's parametric mode does. Each group is a full copy of the active scenario with its geometry changed, so you run, compare and report the steps like any other scenarios.

Set up a sweep

Open Parametric Analysis from the geometry dock. While the window is open its construction lines are drawn on the model; they are not saved and close with the window.

1. Anchor. Click an External Boundary vertex. It stays fixed, and an arc path turns about it.
2. Moving vertex. Click a second External Boundary vertex. The boundary between the two vertices, the chain, is highlighted. Of the two ways round the boundary, the chain is the one that does not pass through the model's lowest vertex.
3. Path. Choose Line or Arc about anchor, then click the end of the path, or type it: the line's end point, or the arc's rotation in degrees (positive turns counter-clockwise).
4. Steps. Choose Points to divide the path into that many equal steps (5 points create 5 groups, the last at the end of the path), or Increment to step by a distance in metres along a line or an angle in degrees around an arc. Increments stop at the last whole step that fits.
5. Create. One group per step is added and the first is loaded. The groups are named by step, for example 03 – Move 6 m or 02 – Rotate 10°.

The model's original group is unchanged.

How the chain moves

Every vertex of the chain moves by a share of the moving vertex's displacement equal to its share of the chain's length, measured from the anchor. A straight face therefore stays straight, and a benched face keeps its benches in proportion. Material Boundary vertices that sit on a moved vertex move with it.

Angle lock

Pick Segments lets you lock chain segments: click a segment, or drag a window across several, to lock them; click again to unlock. A locked segment is moved but never rotated or stretched, for example to keep a berm level and its width fixed. The unlocked segments take up the whole change. At least one segment of the chain must stay unlocked.

A step that would make the External Boundary cross itself is refused, and no group is added.

Terminal

parametric.sweep creates the same groups:

parametric.sweep anchor=3 moving=4 path="line" end=[60,40] count=5
parametric.sweep anchor=1 moving=4 path="arc" angle=10 increment=2 locked=[2]

Vertex and segment indices start at 0; segment i joins vertex i and vertex i + 1.