Scatter Vector: Introduction to Anisotropy
Standard ADMS geometry is near-isotropic: it behaves similarly under load from all directions. Scatter Vector, lets you change this. You can introduce directional stiffness into the ADMS, making it stiffer along one or two defined axes. This article explains what Scatter Vector is, how it works, and when to use it.
What near-isotropic means
An isotropic material behaves the same regardless of which direction you load it. Near-isotropic means it is close to this behaviour but not perfectly uniform. Standard ADMS is near-isotropic because the minimal surface geometry distributes stress in all directions roughly equally.
This is a strength for general lightweighting. But some applications benefit from a structure that is deliberately stiffer in one direction, such as a bracket loaded primarily in one axis, or a component that needs to resist bending without adding mass in the transverse direction.
What Scatter Vector does
Scatter Vector introduces a controlled geometric stretching of the ADMS cell structure along a defined axis. Stretching the cells in one direction makes the structure stiffer in that direction, producing directional stiffness, or anisotropy.
You define this with two components:
- Direction (X, Y, Z): the axis along which the cells are stretched. Must be a non-zero vector. (0, 0, 0) causes an error.
- Magnitude (W): how strongly the stretching is applied, in millimetres. W = 0 has no effect. Increasing W increases the anisotropy.
You can use two independent Scatter Vectors (Scatter Vector 1 and Scatter Vector 2) at the same point to introduce stretching in two different directions simultaneously.
Scatter Vector as a field
Like density and thickness, Scatter Vector is assigned as a field. One assignment creates a constant scatter direction and magnitude throughout the envelope. Multiple assignments at different locations create a spatially varying scatter field, allowing the stiffness axis to rotate or the magnitude to vary across the part.
This is particularly powerful when combined with FEA results: the principal stress direction at each location in the part can be used to define the local Scatter Vector direction, automatically aligning the ADMS stiffness with the actual load paths.
Practical magnitude values
|
W value |
Effect |
|
0 |
No anisotropy. Standard near-isotropic ADMS. |
|
2 to 5 mm |
Mild directional stiffness. Subtle visual change. |
|
5 to 10 mm |
Moderate anisotropy. Clearly visible cell elongation. |
|
10 to 20 mm |
Strong anisotropy. Cells noticeably stretched. |
|
Above 20 mm |
Highly elongated cells. Verify printability before use. |
Scatter Vector and Flow ADMS
Scatter Vector applies to standard ADMS only. It cannot be combined with Flow Direction on the same field point in the current version. If you need both structural anisotropy and flow optimisation in different zones of the same part, use separate envelopes or sub-volumes for each.
When to use Scatter Vector
- The part is loaded primarily in one direction and you want to increase stiffness along that axis without adding mass.
- You have FEA principal stress direction data and want to align the ADMS geometry with the load paths.
- You are designing for a bi-axial load condition and need Scatter Vector 2 to address the secondary loading direction.
- You want to explore structural anisotropy options before committing to a full topology optimisation study.
For purely mechanical applications without a dominant load direction, standard near-isotropic ADMS is usually the better choice. Scatter Vector adds design intent; it is not a universal improvement.