GM_OrientableCurve consists of a curve and an orientation inherited from GM_OrientablePrimitive. If the orientation is "+", then the GM_OrientableCurve is a GM_Curve. If the orientation is "-", then the GM_OrientableCurve is related to another GM_Curve with a parameterization that reverses the sense of the curve traversal.<br /></p><p>GM_OrientableCurve:<br /></p><p>{Orientation = "+" implies primitive = self};<br /></p><p>{Orientation = "-" implies <br /></p><p>primitive.parameterization(length()-s) = parameterization(s)};<br /></p>