When Lightwave builds a polygon, it uses the first three points to determine the direction of the surface normal (which way the polygon is “flipped”).

Unfortunately, the GIS Data has a fairly large number of cases (evidently) where the first 3 or more points in the shape are co-linear, all lined up in a row.

When this happens, Lightwave can’t figure out the direction of the flip, and just chooses one.

What this means, pragmatically, is that of the hundreds of counties in a US map, some will be flipped the wrong direction.

So, the best way to fix the problem is to use an LScript like James Jones DSelect to select the backwards facing polygons, then flip them.

Safety tip: The boundaries are made with two-point polys, and these will cause the select-direction plugins to fail (because two-point polys don’t have a facing direction).

So select all the two-point polys and cut-and-paste them to a separate layer before running DSelect.

These problems should be addressable some day, but who knows when that day is.