In my previous post I described a bug where, when we have a split vertex in an apt.dat layout, X-Plane would draw taxiway lights all over the place. Fortunately, there is a workaround.

Remember that a split vertex is represented as two or three colocated vertices with one or two zero-length segments connecting them. The bug is that zero-length segments cause lights and lines to go haywire.

The fix is therefore simple:

  1. Programs that write apt.dat files can simply set the attributes on the zero-length segment to none.
  2. Future versions of X-Plane (with a real bug fix) can join taxiway lines even when there is a zero-length “break” in the attributes.

This picture shows the results – a split vertex with no attributes on the zero-length segment.

The next WED beta will automatically export split vertices this way – there will be no need to patch X-Plane or change your WED layouts.

About Ben Supnik

Ben is a software engineer who works on X-Plane; he spends most of his days drinking coffee and swearing at the computer -- sometimes at the same time.