With the Advanced User Settings the optimisation parameters can be influenced even further than the options Strut Density and Shape Quality. Furthermore, a few unsupported options are available using the Advanced User Settings like Restart, usage of a Startspaceand aminimum Thickness.
The Advanced User Settings can be added to a Scenario by right clicking on this and selecting the option as shown in the picture below.
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The appearing text field can be used to add Advanced User Commands to the current Generative Design Scenario.
Restart, Usage of a Start Space & Influencing the
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number of iterations
To influence the Strut Density optimisation parameterseven further, changes of the number of iterations , Event Safety Coefficient and number of resolution levels can be made. These settings overwrite the selection of the Strut Densityand the Shape Quality as they are only default settings for the ones described here. The table gives an overview of the default settings:
Input Commands | Explanation |
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schedule.level.0.iterationCount = 8 schedule.level.1.iterationCount = 8 schedule.level.2.iterationCount = 8 schedule.level.3.iterationCount = 8 schedule.level.4.iterationCount = 17 schedule.level.5.iterationCount = 15 | Specify how many iterations are calculated at which resolution level. |
The software uses four six resolution levels from coarse to fine (level 0: coarse - level 35: fine). The number behind the level indicates the number of iterations calculated on this resolution level. To remove or skip a resolution level the value can be set to 0. Moreover, the Event Safety Coefficient for each resolution level can be changed. This coefficient is a scaling factor for the safety factor. More information about the safety factor, stress, failure criteria and resolution here.
To set up these additional parameters, the Input Commands (left side of the table) need to be added to the optimisation model in the Advanced User Settings Text Fieldtext field. In the picture below an example is shown. By adding these Advanced User Settings, the first (coarse) resolution level will be skipped and the optimisation starts directly at the second level. You might want to add more iterations to the remaining levels to give the optimisation the chance to reduce the material accordingly and reach a convergence in each level. Especially level 2 can use more iterations in this case.
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Restart (Start Space)
With the Advanced User Settings a Restart is possible. A Start Space needs to be chosen with which the optimisation will re/start.
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The soft symmetry is activated per default. It influences the design generation so that the part is symmetric in all three dimensions if they were symmetric in the respective dimension to begin with. This is achieved for geometrical symmetrical design spaces even without symmetric LBCs and the hard symmetry constraint.
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This governs how far the optimization value of two symmetric elements is allowed to differ while still being considered equivalent. In theory any value works: the higher the value the more zealously the algorithm will try to keep Soft Symmetry, possibly degrading the quality of the produced geometry compared to a non-symmetric one. The default value is 1e-41.
Attempt Soft Symmetry:
Whether or not Soft Symmetry is attempted at all can be (de)activated here.
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Specifies how many asymmetric voxels elements are sufficient for the "dynamic" setting of attemptSoftSymmetry to turn off soft symmetry. Values between 0 and 1 are allowed, where the number represents the proportion of voxels.
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configuration.equivalenceDelta = 1e-1 configuration.attemptSoftSymmetry = dynamic configuration.softSymmetryThreshold = 0.3 |
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Overhang Angle - Support Reduction
By default an overhang surface is determined if the angle falls below 45° in relation to the baseplate. This angle can be changed with the following command:
45° | schedule.prefabricated.wallAngle=45° |
Minimum Thickness (Experimental Function):
Minimum thickness of a wall, strut or rib and in general all other resulting shapes. Specified in world units (the default is meters!).
configuration.minThickness= 0.002 |
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Frequency Optimisation
By default the first 10 eigenmodes are considered to an upper frequency limit of 3 times the frequency target. This can be modified with the following commands:
event.Event_2.frequencyMax=4500 event.Event_2.frequencyCount=10 |
If the Frequency Constraint is higher than the first calculated Eigenfrequency of the whole Design Space in the first Iteration, this can lead to the case that no material will be reduced. This can be resolved by reducing the Frequency Constraint or by entering the following command to the Advanced User Settings:
schedule.iterations.~.operator.optloop_loop_analysis_Event-2_extractLocalFailures.useMetricGoalFactor=1 |
It has been found that comparable heavy point masses can cause that the optimisation does not achieve the Frequency Constraint. To address this the impact value can be set up to a value greater than 1. This can be done with the following Advanced User Settings command:
event.Event_2.impact=1.5 |
| Info |
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Event_2 has to be replaced with the name of the frequency event. |
RBE2 (rigid connector) can be used as a connection type for a Point Mass, but the RBE2 connection won’t be considered in a static load case. This can occur if a Point Mass is added in combination with acceleration.
pointMass.PointMassInertia_Point_Mass_1.type=RBE2 |
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