Symmetry

The symmetry function is a feature of the User Interface and helps to set up symmetrical optimisation models very fast and easy. For more information regarding the setup of a symmetric optimisation model have a look here.

The symmetry function is activated right at the beginning of the workflow in the Design Space Tool. The details of the symmetry function are displayed and can be specified.

Open

At least one and at most all three symmetry planes have to be defined. MSC Apex Generative Design automatically detects suitable symmetry planes for the part. These can further be modified by shifting the origin of the symmetry planes or by rotating the symmetry axis. When confirming the selection, the Principal Coordinate System (PCS) is updated with the information of the just defined symmetry coordinate system.

Note: Changes to this coordinate system result in a change to the Principal Coordinate System and can therefore also change the material orientation and the build direction!

Changing the Principal Coordinate System afterwards doesn’t update the symmetry coordinate system and therefore the created symmetry Design Space. The orientation needs to be taken into consideration at this step. The build direction is the z-axis (blue) and shouldn’t be chosen normal to a symmetry plane.

Open

Additionally, to the Design Space Solid, a Design Space Object appears inside the model tree. The Solid is the half/quarter/octant on which all the boundary conditions can be applied. The Design Space Object is transparent and will mirror all geometry changes as well as the boundary conditions.

Tip: 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.

Symmetric Optimisation Conditions

With the Symmetry function a symmetrical result can be realized. Therefore, the geometry and the boundary conditions have to satisfy some conditions. The User Interface takes care that these conditions aren’t violated. If the command line optimisation is used, please be aware of the following 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.

• Gravity loads normal to the symmetry plane will cancel each other out

Calculation Type: Preview

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 optimisation runs through.