Extrude Along Curve going wrong direction sometimes

I’m trying to extrude some hexagons along computed curves. In preview, the the hexagons and curves look happy:


But when actually extruded, some of them go the wrong direction, and seem to flip the curve in the Z axis before extruding:

I’m at my limited wits’ end. Thoughts on what’s going on here?

hexavase.gh (17.5 KB)

I just cleaned up some of your trees/null values. See attached.

hexavase_rev3.gh (18.4 KB)

Extrude along curve does not rely on the actual location of the curve, only the curves shape and direction. That shape is interpreted from the profile onward. (Essentially a sum surface). The flipping is because some of your curves are flipped (they start at the higher point of the curve and are drawn downward). Flip those curves direction.

Thank you! That’s been bothering me.