Warning: No intersection found with any panel in center-of-pressure calculation.

This warning is printed when running the example `pyramid_model.jl`:
```julia
┌ Warning: No intersection found with any panel in center-of-pressure calculation.
└ @ VortexStepMethod ~/repos/VortexStepMethod.jl/src/body_aerodynamics.jl:643
```
Why?

The examples should not print warnings.