With the Advanced User Settings the optimization 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 Startspace, Symmetry and Intersection.
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 Startspace & 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 Density and 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 |
|---|---|
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 optimization. |
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 balanced: 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 balanced: 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 optimization 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 optimization starts directly at the second level. You might want to add more iterations to the remaining levels to give the optimization the chance to reduce the material accordingly. 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 optimization will re/start.
Therefore, an already optimized STL-file is needed as Start Space. This can be exported directly from the post processing and 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.
This way a two-stage optimization is also possible. For a two-stage optimization the resolution level and number of iterations must be chosen wisely and will need some fine tuning.
Symmetry
With the Advanced User Settings a symmetrical result can be realized. Therefore, the geometry and the boundary conditions have to statisfy some conditions:
The geometry needs to be symmetrical
The boundary conditions need to be symmetrical
The loads have to be applied only on a half/quarter/eighth of the part. They will be automatically mirrored and considered through the symmetry planes. Forces have to be applied on volumes/cells.
Attention: The loads are only allowed to be applied in the positive coordinate direction (positive cooridnate half/quarter/octant)
The displacement constraints are allowed to be applied on a volume/cell that goes beyond the symmetry plane to the other coordinate half/quarter/octant unlike loads
The geometry needs to be located in the global coordinate origin
To activate a symmetry the following commands can be typed into the Advanced User Settings Text Field:
symmetry.x (Y-Z-Plane is symmetry plane)
symmetry.y (X-Z-Plane is symmetry plane)
symmetry.z (X-Y-Plane is symmetry plane)
The symmetry constraint might not show exactly symmetrical designs while choosing the calculation type “Preview”. This is because of the low resolution level but will not occur once the calculation type is set to “Balanced” or “Fine Tune” and the optimization runs through.
Hint: Only a half, a quarter or an eighth of the model will be calculated. Thus, only a half, a quarter or an eighth of the calculating resources are needed.
Note: The symmetry option is currently an unsupported function!
Intersection
Intersections between optimization 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.
An intersection can be done after the optimization in the Apex user interface. Further information here.
Another option to create intersections automatically and simultaneously with the optimization is to use the Advanced User Settings. Therefore, the following export command has to be added to the text field:
export_stl_name_MC_Smooth_intersection
The intersected STL-files will be saved inside the project folder in the workspace for every iteration.