Restart Optimisation - Bookshelf

This tutorial shows how to perform a Restart of a stopped optimisation. Therefore, the Advanced User Settings are needed. More information regarding the background of a Restart here.

With this option a terminated optimisation can be continued. To realize a Restart another geometry can be chosen as the Start Space instead of the Design Space. In this case the optimisation starts with the specified geometry although the whole Design Space is still the geometry limitation for the optimisation.

The Start Space STL-file needs to be entered into the optimisation in the same unit system the model is in!

Start Space STL-file

The Start Space for a Restart must be a STL-file. Therefore, an already optimised geometry can be exported in the Post Processing. In this case iteration 22 from the Bookshelf Tutorial will be used.

Open

Attention: The STL-file for the Restart should be exported in SI-Unit system (meters) to fit the unit system the optimisation will run with.

Optimisation Setup

In the next step a new Scenario should be created for the Restart optimisation. Therefore, the already existing Scenario can be cloned.

With the Advanced User Settings - available through a right click on the Scenario - the Start Space STL-file can be selected. In this case the exported iteration 22 is selected.

The most important part of a Restart is to add and adjust the Advanced User Settings especially the number of iterations, the resolution level and the stress goal percentage. More background information regarding the Advanced User Settings here.

In this example the Bookshelf should be restarted as if the optimisation never stopped, so with the same optimisation parameters as the first optimisation and excluding the already done iterations. Therefore, the settings for the parameters Strut Density: Medium and Shape Quality: Balanced are added to the Advanced User Settings and adjusted according to the number of iterations already calculated. Which number of iterations and which Event Safety Factor should be input for each resolution level can be found here.

42 iterations must be added to reach the total number of 64 iterations (Shape Quality: Balanced).

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The information are added in the Advanced User Settings in the following style:

schedule.level.0.iterationCount = 0
schedule.level.1.iterationCount = 17
schedule.level.2.iterationCount = 20
schedule.level.3.iterationCount = 5
schedule.level.0.eventSafetyCoefficient = 0.3
schedule.level.1.eventSafetyCoefficient = 0.4
schedule.level.2.eventSafetyCoefficient = 0.9
schedule.level.3.eventSafetyCoefficient = 1

After adding these commands to the Advanced User Settings the optimisation can be started. The first iteration of the restarted optimisation will be the imported Start Space.

You can check the status of the optimisation in the GD Status and get more information on Warning and Error messages. This can be done directly in the Post-Processing as well as in the Studies tab for an optimisation that has already run.