Metamaterials Analysis
Metamaterials analysis designs periodic microstructures (unit cells) with engineered mechanical properties. The solver optimizes the geometry of a single unit cell that, when tiled, produces a metamaterial with target behaviors such as negative Poisson's ratio, programmable stiffness, or directional compliance.
The solver uses the same AI-driven design optimization approach as compliant mechanisms. The difference is in how boundary conditions are applied and how results are tiled into a full metamaterial sheet.
When to use metamaterials analysis
Use Metamaterials when:
- You need to design a repeating unit cell pattern.
- The mechanism behavior is defined at the cell level and intended to be tiled across a larger structure.
- You want to fill a complex 3D shape with optimized metamaterial by uploading a STEP file and assigning face constraints.
- You need to control mechanical properties (stiffness, Poisson's ratio) at the material level rather than the structure level.
Do not use metamaterials analysis when:
- You need a single non-repeating mechanism. Use Compliant Mechanism 2D or Compliant Mechanism 3D instead.
- You need concentrated flexure hinges. Use Flexure Analysis instead.
How metamaterials differs from other analysis types
| Aspect | Compliant Mechanism | Metamaterials |
|---|---|---|
| Design output | Single mechanism | Tileable unit cell |
| Obstacles | Supported | Supported |
| Preserve pairs | Supported | Supported |
| STEP face constraints | No | Yes (in Metamaterials preserve mode) |
| Full metamaterial tiling | No | Yes (generates tiled output from unit cell) |
Preserve modes
Metamaterials analysis supports all three preserve modes:
Separate mode (default)
Standard input/output/fixed preserve layout, identical to compliant mechanism analysis. The solver optimizes a unit cell with the specified boundary conditions. This is useful when you define force inputs and motion outputs at cell boundaries.
Combined mode
Uses combined I/O preserves for combined input/output boundary conditions, routing to the flexure solver algorithm.
Metamaterials mode (STEP upload)
This is the mode unique to metamaterials analysis. Instead of placing preserves manually, you upload a STEP file that defines the full 3D part shape, then assign constraints to individual faces on that model.
STEP upload workflow
- Switch to Metamaterials mode using the preserve mode toggle.
- The sidebar shows a Part Shape (STEP) section with an upload area.
- Upload a
.stepor.stpfile. The file is parsed locally in the browser, then uploaded to the server. - Once uploaded, the STEP model appears in the viewport and a Face Constraints section appears below.
- Click Select Faces to enter face selection mode. Click faces on the 3D model to add them as constraints.
- Configure each selected face as DOF or Fixed.
- Click Done to exit face selection mode.
The uploaded STEP file is linked to the analysis. You can remove the file and upload a different one at any time.
Face constraints
Each selected face on the STEP model is configured as either a DOF (degree of freedom) or Fixed constraint.
DOF faces have:
| Property | Description |
|---|---|
| Direction vector | A 3D vector (x, y, z) defining the allowed motion direction. |
| DOC constraints | Checkboxes for which degrees of constraint to apply. Index 0 is "Perpendicular" and index 1 is "Rotation (rz)". At least one must be enabled. |
Fixed faces have no additional properties. They constrain the face to remain stationary.
Each face constraint card in the sidebar shows the face index, a DOF/Fixed toggle button, and (for DOF faces) the direction and DOC inputs. A trash icon removes the face constraint.
In Metamaterials mode, the standard Fixed preserve section is hidden since boundary conditions are defined through face constraints instead.
Tiling and full metamaterial generation
When full metamaterial generation is enabled, the solver generates a tiled metamaterial from the optimized unit cell after the final iteration. The tiling dimensions are controlled by:
| Parameter | Description |
|---|---|
| Metamaterial Width | Total width of the tiled output in mm. |
| Metamaterial Height | Total height of the tiled output in mm. |
The resulting full metamaterial is stored as a special solver result. In the properties panel for a full metamaterial result, you can adjust the target dimensions and regenerate the tiling.
Solver parameters
Metamaterials shares most solver parameters with Compliant Mechanism 2D:
| Parameter | Default | Description |
|---|---|---|
| Iterations | -- | Maximum optimization steps. |
| Volume Fraction | -- | Target material fraction (0.1 -- 0.9). |
| Element Size | -- | Mesh element size in mm. |
| Penalization | 7.0 | Controls design sharpness (higher values produce crisper solid-or-void designs). |
| Filter Radius | -- | Feature size control radius. |
| Mechanical Advantage | -- | Output/input displacement ratio. |
Additional parameters
| Parameter | Description |
|---|---|
| Symmetry (vertical/horizontal) | Enforce mirror symmetry in the unit cell. |
| Constrained Rotation | Fix rotation centers in space for motor-like behavior. |
| Stress Constraint | Enable von Mises stress constraint with configurable yield strength and factor of safety. |
| Penalization Scheduling | Linearly increase the design sharpness over the final iterations for crisper results. |
Validation requirements
In Separate or Combined mode, validation follows the same rules as compliant mechanism analysis: at least one input (or I/O) preserve with geometry and path, at least one output preserve with geometry and path (Separate mode only), at least one fixed boundary, and a material selection.
In Metamaterials mode, the STEP file must be uploaded and at least one face constraint must be defined.
Related pages
- Preserve Modes -- how the three modes change the sidebar layout
- Compliant Mechanism 2D -- shares the same solver algorithm
- Object Types -- face constraint type reference
- Solver Parameters -- full parameter reference