> For the complete documentation index, see [llms.txt](https://docs.aviumtechnologies.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aviumtechnologies.com/user-guide/solver/symmetry.md).

# Symmetry

The APM solver supports symmetry solutions across the x-z plane. When using the symmetry option the solver calculates the influence coefficients 2x faster and requires 2x less memory. To enable the symmetry option, set the `symmetry` option to 1 in the **.conf** file. Note that any motion that you prescribe (if performing an unsteady simulation) must honour the x-z symmetry requirements. This means no velocity components in the y-direction or non-zero sideslip angle! The image below shows the comparison of the wake between symmetric and non-symmetric solutions.

<figure><img src="https://81269019-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MV8htLPXN-_fWc_anY_%2Fuploads%2Fhl1tYSjfEf6vqysZE50M%2Fsymmetric_solution_comparison.png?alt=media&amp;token=9ffcccc7-12a5-400f-a0e3-66f71aee146c" alt=""><figcaption><p>Symmetric and non-symmetric (not assuming) symmetry of a fixed-wing UAV.</p></figcaption></figure>