Post Processing

After starting an optimisation MSC Apex Generative Design automatically switches to the Post Processing. When an optimisation is finished the results of the project can always be visualized inside the post process.

Live View

In the live Post Processing, the iterations of the optimisation are displayed as soon as they are available. The current iteration is shown and the number is displayed at the bottom progress bar. Furthermore, the progress bar shows the planned number of iterations. The Design Space can be displayed by selecting the button Initial Shape beneath the progress bar. The optimisation can be aborted by selecting the stop button next to the scenario in the left top corner. After finishing or aborting the optimisation the Post Process can be left with the exit button in the right bottom corner.

Automatic Intersection

The shown results of the Nominal-Geometry inside the Post Processing are automatically a Boolean intersection between the optimisation result and the initial Design Space. This ensures all sharp edges and functional surfaces are available and the generative designed part is inside the boundary limits. This automatic intersection leads to a lower number of polygons in this area which can lead to a lower resolution stress plot. This is only a visual issue inside the Post Processing.

Failure Criterion

The Failure Criterion can be chosen in the studies tab for every optimisation scenario. Dependent on the intention of the optimisation it can be chosen between the equivalent von Mises Stress, a FFF Thumb Rule or directional dependent Tsai-Hill or Tsai-Wu Failure Criteria. More information regarding the Failure Criteria here.

In combination with the Safety Factor and the material properties (material limits) the Failure Criterion is the objective of the optimisation. The target is to load all the material with a value of 1 of the chosen Failure Criterion.

E.g. for isotropic material behaviour the Failure Criterion can be the von Mises stress. The Failure Criterion is the von Mises Stress distribution normalized to the value which corresponds with the chosen Stress Goal. The Stress Goal is calculated with the tension strength of the material and the safety factor. Values above one exceed the optimisation target, values beneath show areas with more optimisation potential. The maximum value can be displayed in a chart over the number of iterations.

For the other Failure Criteria the material directional dependency regarding the tension, shear and/or the compression strength is considered.

Stresses

If the Failure Criterion is set to von Mises the approximated von Mises stress is shown as a coloured plot.

By default, the maximum stresses of all Events are shown in one plot. Therefore, the stresses from all Events are enveloped and the highest stress for each area is shown. In the right top corner, the scale from zero to the maximum of this iteration is displayed. The stresses in the colour plot and visualization area are smoothed values of the element representation and therefore estimated values. The goal of generative design is to create a lightweight design which is as close as possible to the elected stress goal.

The stress for each Event separately can be displayed by choosing a specific Event (see picture below).

By selecting the point chart, the stress curve over the iterations can be displayed. The maximum stress is used for this chart. Inaccuracies because of FE singularities or stress exceeding because of boundary conditions are included.

Scale

The scale can be influenced by expanding the scale window with the arrow in the top corner.

It can be chosen between a discrete and a continuous spectrum. The scale can be changed by replacing a number with a distinctly chosen number. The default scale spectrum can be set to 2 times the stress goal, which is a good fit for all optimisations. This displays the even distribution of the selected stress goal with the colour range of green and critical points are viewable in red. The fixated Non-Design Spaces are displayed in blue because no stresses can occur in these areas. At the bottom out of range colours can be activated, which show areas which are above or under the adjusted scale. Moreover, the spectrum can be locked to compare different iterations with the same spectrum.

Displacements

By selecting the displacement button, the translational displacements are shown. It can be switched between the resultant or the component displacement for each direction.

Mass / Volume

By selecting the mass and/or the volume point chart, the mass/volume curve over the iterations is displayed.

Attention: The displayed mass refers to the Nominal-Geometry taking into account the density of the material. If Retained Volumes are included, the mass is estimated based on the different densities of the volumes.

Experimental Function: Optimisation Achievement Index

The Optimisation evaluation is displayed in the Optimisation Achievement Index. This shows in which areas the optimisation goal was reached, was exceeded or where there is more potential. So this value gives an indication in which areas the structure will change in the next iteration either by growing or reducing elements regarding to the colour.

Geometry Output and Result Export

The buttons in the bottom bar give the opportunity to switch between three different geometries.

The Nominal-Geometry is the default geometry on which all stresses and displacements are plotted. This Geometry is intersected with the Design Space and is the final Geometry.

The Smooth-Geometry is the optimisation result without any intersection. If you have added Machining Allowances or the automatic Non-Design surface growth is activated (default), the geometry will extend beyond the boundary limits from the Design Space in areas of Non-Design Spaces. This Geometry should be used for a retransitioning to a NURBS-Geometry. This Geometry is suitable for an intersection between the retransitioned optimisation result and the Design Space. If the optimisation contains Retained Volumes, these will also be part of the Smooth Geometry.

The Print-Geometry is the Geometry which can be directly manufactured. It includes the extra material from the applied Machining Allowances which can be removed in a precise machining process like milling.

All of these three geometries can be exported as an STL-file by selecting the button Export Design Candidate (beneath the progress bar). Because Generative Designs can be very complex, we recommend saving files as Binary-STLs.

Build Direction

If a Build Direction was entered during the model set up it can be visualised in the Post Processing as well.

Result Files

You can find all result files as well as the different log files of the optimisation in your workspace. Per default your workspace is defined as:

C:\Users\ExampleUser\Documents\Apex Generative Design Workspace

In this parent folder you can find a separate folder for each project you have saved. In these you can find your latest optimisations (named after your scenario).

For example: exampleProject/GD Scenario 1 Step 1.v1