I have a general problem when automating a part. For example, imagine a horizontal line, the code includes vertical distance values of a set of points about that line. Eventhough the distance values are positive, Nx locates some of the points below the horizontal line. Sometimes it happens when using splines instead of horizontal line. There should be a side control option which you can always put those points above or below reference line or spline.
The image shows how the situation occurs. The height parameter is positive but sometimes it puts the point below the line even it has still positive value.
-The ref line in the image is the projection of a sketch line.
-The situation happens also when using a ref spline and it has a point on the curve. There is a line on that point and perpendicular to spline. The height of line is controlled by a dimension. Even the dimension always positive, the end point of line sometimes moves above the spline and sometimes moves below the spline as the dim changed.
It looks like you're controlling the point location by using an expression that produces a dimension value.
The problem is that dimensions simply express *distances*, and distances are not signed.
So, suppose I have a horizontal line L with equation y = a. Then I define a point P = (x,y), and I define a constraint that says distance(P,L) = b. The points (x, a+b) and (x,a-b) both satisfy this constraint, and you haven't provided any information to indicate which one you want.
If the line is horizontal, you might argue that the point should be "above" the line when b is positive. But when the line is angled, there is no reasonable definition of "above".
So, I think you need some alternative method of locating your point.