Non-planar graph when using external generator with non-default embed iteration count

[nvcleemp]

Select a non-default embed iteration count in the external generator panel. Visualise the graph in 2D. If you do this to display, e.g., a fullerene then the resulting image as many crossing edges.

[nvcleemp]

The cause of this is that the factor for the last phase of the 2D embedder is set to a non-zero value.