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Configure Analysis Settings

The Analysis Settings panel contains all solver parameters that control how the design optimization runs. Open it via the Analysis toolbar button or by selecting the analysis node in the scene tree.

Core parameters​

These two fields appear at the top of the panel for every analysis type.

Volume fraction​

The target fraction of the design domain to fill with material. Default is 0.30. Accepts values from 0.05 to 0.90 (step 0.05).

Lower values produce lighter, more flexible designs. Values below about 0.10 may cause convergence difficulties because the optimizer has very little material to work with. Values above 0.70 leave little room for the optimizer to remove material, which limits the design freedom. See Configure Volume Fraction for guidance on choosing a value.

Convergence tolerance​

The maximum change in any design value between iterations that triggers early stopping. Default is 0.01. Accepts values from 1e-8 to 0.1.

Smaller values demand tighter convergence but may require many more iterations. A value of 0.01 gives rough results quickly; values around 1e-5 produce highly refined designs.

Solver type (Compliant and Decoupled Flexure)​

This section appears for Compliant Mechanism and Decoupled Flexure analysis types.

Nonlinear Analysis​

A checkbox (labeled "Nonlinear" in the UI) that switches the structural analysis solver from linear to nonlinear. Default is off.

When enabled, the solver uses a nonlinear formulation that accounts for geometric nonlinearity (large deformations). This is important for compliant mechanisms that undergo significant deflection, where linear assumptions break down.

Enabling nonlinear analysis reveals two additional fields:

  • Material model -- Selects the constitutive model used in the nonlinear solve. Options:

    • Linear Plane Stress (default) -- Standard linear elasticity in a plane-stress formulation.
    • Saint Venant-Kirchhoff -- A hyperelastic model valid for large strains with linear stress-strain relationship in the reference configuration.
    • Yeoh Hyperelastic -- A phenomenological hyperelastic model suitable for rubber-like materials.
    • Neo-Hookean -- A simple hyperelastic model for moderate strains.

  • Threads -- Number of threads for the nonlinear solver. Leave blank for automatic thread selection. Accepts values from 1 to 64.

Stress constraint (Compliant and Decoupled Flexure)​

Controls whether the optimizer enforces an upper bound on stress during optimization.

Enable​

A checkbox that activates the stress constraint. Default is off.

When enabled, two parameters appear:

  • Max Stress -- The yield strength used as the stress limit, in the current pressure unit. Default is 250. Accepts values from 1 to 2000 (step 10). If you have selected a material, this value is typically set from the material's yield strength.

  • Safety Factor -- Applied to the max stress to create the actual constraint limit (effective limit = max stress / safety factor). Default is 1.5. Accepts values from 1.0 to 5.0 (step 0.1).

Mechanical advantage and stiffness (Separate mode)​

When the analysis uses separate preserve mode, additional fields appear.

J* (Mechanical Advantage)​

The target output-to-input ratio for the mechanism. Adjustable in steps of 0.1. A negative value inverts the output direction. This drives the optimizer to produce a mechanism that amplifies or de-amplifies input motion by the specified ratio.

K_p_max (Stiffness constraint)​

For each preserve pair in the scene, a field appears showing the maximum characteristic stiffness constraint. Default is 10.0 (step 0.1, minimum 0.1). In Robust formulation mode, these fields are disabled because the robust formulation handles stiffness internally.

Combined (Flexure) mode settings​

When the analysis uses combined preserve mode (not separate), different parameters appear:

  • Max Strain Energy -- Upper bound on strain energy. Default is 3.0 (step 0.5, minimum 0.1).
  • Prescribed Displacement -- Only visible for 3D scenes. The prescribed input displacement in the current length unit. Default is 1.0 (step 0.1, minimum 0.01).
  • Max Stress -- Material stress limit in the current pressure unit. Default is 100 (minimum 1).

Metamaterial tiling (Compliant only)​

Available only for Compliant Mechanism analysis types (not Decoupled Flexure). This section is collapsed by default and opens if tiling is already enabled.

Generate Tiled​

A checkbox that enables full metamaterial generation from the optimized unit cell. Default is off.

When enabled:

  • Total Width -- The total width of the tiled metamaterial, in the current length unit. Minimum is the design domain width; step size equals the domain width (for whole-number tiling).
  • Total Height -- The total height of the tiled metamaterial. Same constraints as width.

Thermal settings (Decoupled Flexure only)​

This section appears only for the Decoupled Flexure analysis type and is collapsed by default.

  • CTE (1/K) -- Coefficient of thermal expansion. Default is 8.6e-6 (step 1e-6). This field is disabled when a material is applied, since the CTE comes from the material database.
  • T_start (K) -- Starting temperature in Kelvin. Default is 293 (step 10, minimum 0).
  • T_end (K) -- Ending temperature in Kelvin. Default is 120 (step 10, minimum 0).
  • Delta T -- Read-only display showing the computed temperature difference (T_end - T_start) in Kelvin.

Advanced settings​

The Advanced section is collapsed by default. These settings are for expert users and affect the internal behavior of the optimization algorithm.

Penalization​

Controls design sharpness. Default is 3 (range 1 to 10, step 0.5). Higher values produce crisper, more clearly defined designs. See Solver Parameters for a detailed explanation.

Filter radius​

Radius of the design refinement filter. Default is 1.5 (range 0.5 to 5, step 0.1). Controls minimum feature size and prevents numerical artifacts.

Force full density​

When checked (default), preserve areas are forced to full material density. Unchecking allows the optimizer more freedom but may produce designs where preserve regions are partially hollow.

Formulation​

Selects the solver formulation strategy:

  • Nuanced (default) -- Fine-tuned stiffness control mode.
  • Robust (2001) -- General-purpose mode for reliable results.

Penalization scheduling​

When enabled, the penalization value increases progressively during the optimization run:

  • Start (iters) -- Iteration at which ramping begins. Default is 10.
  • Final Penalization -- The penalization value at the end of the ramp. Default is 15.0 (range 1 to 30).

Stiffness scheduling​

When enabled, the workpiece spring stiffness is adjusted dynamically:

  • Target u_out -- Target output displacement. Default is 1.0.
  • Scale Factor -- Multiplier for stiffness adjustment. Default is 1.0.
  • Max Multiplier -- Upper bound on the stiffness multiplier. Default is 10.0.
  • Base K (N/mm) -- Base workpiece spring stiffness. Default is 10.0.

Force scheduling​

When enabled, the applied force magnitude ramps during optimization:

  • Mode -- Currently only Linear is available. Metric-Based mode is planned.
  • Force Multiplier -- Maximum force multiplier at the end of the ramp. Default is 2.0.

Other advanced options​

  • Constrained Rotation -- Constrains rotational degrees of freedom during optimization.
  • Legacy optimizer -- Uses the legacy optimizer implementation.
  • Mirror Vertical -- Enforces vertical symmetry in the optimized design.
  • Mirror Horizontal -- Enforces horizontal symmetry in the optimized design.
  • Qualification Analysis -- When checked (default), a post-optimization qualification analysis is automatically run on the final result. See Test a Mechanism for details on qualification analysis results.

Read-only scenes​

All fields are disabled when viewing a scene you do not own.