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 preventing an Intersection during the optimisation.
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.
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 Strut Density
To influence the Strut Density even further, changes of the number of iterations, stress goal percentage 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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UpSampleConfig fOptimizer_switchAddRemove=58 | Starting with iteration 58, elements are either added or removed and only every second iteration is saved. This is important for the iterations near to the end of the optimisation. |
iteration .level_3=20 .level_2=20 .level_1=20 .level_0=4 | Specify how many iterations are calculated at which resolution level. Note that convergence should be achieved at each level. Default settings medium: 20, 20, 20, 4 Default settings sparse: 16, 40, 4, 4 Default settings dense: 10, 10, 40, 4 |
Optimizer_stressPercentGoal .level_3=30 .level_2=40 .level_1=90 .level_0=100 | The percentage at which the target stress is reached is set. Default settings medium: 30, 40, 90, 100 Default settings sparse: 60, 90, 95, 100 Default settings dense: 10, 25, 50, 100 |
The software uses four resolution levels from coarse to fine (level 3: coarse - level 0: fine). More or less resolution levels can be added or removed. The number behind the level indicates the number of iterations calculated on this resolution level. Moreover, the stressPercentGoal for each resolution level can be changed. More information about the stresses 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 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.
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.
Therefore, an already optimised STL-file is needed as a Start Space. This can be exported directly from the post processing and be selected as a Start Space by clicking on the browse button. Therefore, the unit of the exported STL-file needs to be in meters (SI-Units). In most cases the Strut Density and Shape Quality settings must be changed as well using the Advanced User Settings. For a restart the same resolution level and number of to be completed iterations have to be filled in. You can find a Tutorial to how to perform a Restart here.
This way a two-stage optimisation is also possible. For a two-stage optimisation the resolution level and number of iterations must be chosen wisely and will need some fine tuning.
Preventing an Intersection
Intersections between optimisation results and the Design Space are needed to create the final, manufacturable design. This ensures all functional sharp edges are available and the generative designed part is inside the boundary limits.
The intersection is done automatically for every iteration. Therefore, the defined Design Space is intersected with each result iteration.
If an intersection is not directly requested, the command “noIntersection” can be added to the Advanced User Settings. In some cases the Design Space of the optimisation is not the one the intersection should take place with and therefore this additional command can be used. The intersection is not done for the iteration but the result is the smoothed optimisation design. For further information regarding a separate intersection with MSC Apex Generative Design have a look here.
Disable Automatic Non-Design Growth
Per default all Non-Design surfaces grow a little bit beyond their boundaries to ensure a trouble-free and clean intersection. This is done with an automatic detection of Non-Design faces. Sometimes this can lead to issues.
Every time when Machining Allowances are applied on all functional surfaces this function can be deactivated. Even if this surface won’t be post processed and no additional material is needed, a Machining Allowance of 0 mm can be applied. This ensures sharp edges and planar, functional surfaces after the intersection.
How the automatic Non-Design growth influence the resulting geometry here.
This automatic growing can be deactivated with the Advanced User Settings command below:
automaticFunctionalFacesDetection.positiveNonDesignDirection=false |
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If this command is activated, pressure loads are not considered in the optimization. This combination of options is currently unsupported.