In the Solver Settings tab, define the parameters for the FreeWeave Solver.

The FreeWeave solver performs a physical simulation when generating the weave in an iterative process. During the simulation, the threads are tightened while the interaction between the threads is considered, such as collisions.

The Tolerance stands for the height reduction of the weave due to the simulated tightening between subsequent iteration steps. The simulation stops if the height reduction is below this threshold for several iterations. This does not work for all kind of weaves. Thus, another stopping criterion is the Maximal Iterations, where the solver stops once the entered number of iterations is reached. Both criteria can be selected at once and the solver run stops when one of the two is satisfied.

Threads are divided into linear segments and their Segment Length is relative to the minimum thread diameter. The Segment Min. Length should be less than half of the Segment Max. Length.

The Max. Relative Step-Size and Max. Absolute Step-Size define how much a thread may be moved in an iteration. The Max. Absolute Step-Size is defined by the given value multiplied with the smallest fiber diameter. It should be smaller than 0.5, to avoid fibers “jumping over” other fibers with which they collide. The value for the Max. Relative Step-Size is multiplied with the length on which two fibers overlap and should be smaller than 1 for a stable simulation. In case of overlap, the smaller value of Max. Absolute Step-Size and Max. Relative Step-Size size is used.

After either Tolerance or Maximal Iterations stopping criteria are fulfilled, the fibers are subdivided into smaller segments over several iterations given by Refinement Iterations. These iterations are done in an additional solver run pass.

The Refinement Factor defines to which extent the Minimum and the Maximum Segment Length are reduced at the end of the refinement iterations. A value of 0.1 means that the Minimum and the Maximum Segment Length are reduced to 10% of their start values. The Refinement Factor is a number that is larger than or equal to 0.1 and less than or equal to 1. If the Refinement Factor is set to 1, this feature is disabled and no Refinement Iterations are performed.

Smoothing Subdivision performs a subdivision and spline interpolation as a post-processing step after the simulation. The primary use for this is in visualization to make the structure appear smoother. As it happens only once at the end of the simulation, it is not computationally expensive to use. The number given here is the number of subdivisions to perform and it is thus a positive integer number. A value of 1 will perform no subdivision. A value of 2 will split each segment into two segments etc. In most situations, increasing the value beyond 3 will not give a noticeable improvement.

If Fix Lateral Warp Shift is activated, the entered lateral deformation of the warp threads is fixed during the creation of the weave. This means the warp threads cannot move along the lateral direction.

The option Add Periodic Copies helps to prevent problems when exporting a mesh of the structure. If this option is enabled, periodic copies of one unit cell are added in each direction of the X-Y-plane. The periodic copies are only stored as GAD information (analytical object information) and have no influence on the voxelized geometry. It is not necessary to check this option when the structure is used only in GeoDict. If the structure should be exported to a mesh (with ExportGeo-CAD of MeshGeo), this option should be enabled to prevent artefacts at the domain boundary.

Clicking on Advanced Options unfolds many more settings. For most of the simulations they need not to be changed. If they need to be adjusted, tooltips describe how they can be used.