Spline with an array

hervé_pipon

Hello

I need some help with the spline.

I wrote a feature which draw a spline from a csv file

Inside I use this code

} else if (linetype == "C") {
            var P1 = point_courant;
            var P2 = vector(aline[1], -aline[2]) * ZoomCoefficient + splineOffset;
            var P3 = vector(aline[3], -aline[4]) * ZoomCoefficient + splineOffset;
            var P4 = vector(aline[5], -aline[6]) * ZoomCoefficient + splineOffset;
        
            var start = P1;                                
            var end = P4;
			var startDerivative = 3 * (P2 - P1);
            var endDerivative = 3 * (P4 - P3);

            skFitSpline(sketch1, "spline_"~ entityCount*100, {
                "points": [
                    start,
                    end
                ],
                "startDerivative": startDerivative,
                "endDerivative": endDerivative,
            });
            point_courant = P4;
        }

Unfortunately the display is not the same as with the spline tool

There is lots of "glued splines" but not a single smooth curve
-- In green a spline created with the spline tool : separation are shown only when curve is a line.
-- In blue the one from my featureScript  : separation are shown for each points of the spline

I changed my way to draw all the connected point at once with this code

1/ first detect the end of point list to draw all at once  

if ((lastlinetype == "C") && (linetype != "C")) {
            if (splineopened) {
                print("spline_"~ entityCount);
                print(" = ");            
                skFitSpline(sketch1, "spline_"~ entityCount , {
                    "points": splinePoints,
                    "startDerivative": startDerivative,
                    "endDerivative": endDerivative,
                });
                println(splinePoints);
                splinePoints = [];
                splineopened = false;
            }
        }

2/ and instead of drawing the curve, I memorize the points in a list

} else if (linetype == "C") {
            var P1 = point_courant;
            var P2 = vector(aline[1], -aline[2]) * ZoomCoefficient + splineOffset;
            var P3 = vector(aline[3], -aline[4]) * ZoomCoefficient + splineOffset;
            var P4 = vector(aline[5], -aline[6]) * ZoomCoefficient + splineOffset;
        
            var start = P1;                                
            var end = P4;
            endDerivative = 3 * (P4 - P3);
            splinePoints = append(splinePoints, start);
            splinePoints = append(splinePoints, end);
            if(splineopened == false) {
                startDerivative = 3 * (P2 - P1);
            }
            splineopened = true;
            point_courant = P4;
        }

But it does not work!!! 

And I don't understand what is wrong

Can you help ?