Best way to duplicate a spline with an offset

[Kapistijn]

Thanks for the quick response.

I've implemented a custom solution, but I'm getting stuck on calculating the tangent.

Code:

private Vector3 CalculateOffset(CurvySplineSegment originalSplineSegment)
        {
            if (m_CurvySpline == null || originalSplineSegment == null)
                return Vector3.zero;

            Vector3 tangent = m_CurvySpline.GetTangent(originalSplineSegment.TF);
            Vector3 perpendicularTangent = Vector3.Cross(tangent, originalSplineSegment.transform.up);

            Vector3 offset = perpendicularTangent * m_Offset;

            Debug.DrawLine(originalSplineSegment.transform.position, originalSplineSegment.transform.position + (tangent * m_Offset), Color.yellow, 10.0f);
            Debug.DrawLine(originalSplineSegment.transform.position, originalSplineSegment.transform.position + (perpendicularTangent * m_Offset), Color.red, 10.0f);

            return offset;
        }

In the attachment you can see the yellow line representing the perpendicular. But I'm expecting a vector more like the purple one.
Am I doing something wrong to calculate the perpendicular? Or am I misinterpreting what the tangent actually is?

Thank you so much in advance!