public override void Evaluate(FSharpList <Value> args, Dictionary <PortData, Value> outPuts)
{
var pts = ((Value.List)args[0]).Item;
if (pts.Length < 3)
{
throw new Exception("3 or more XYZs are necessary to form the best fit plane.");
}
var ptList = BestFitLine.AsGenericList <XYZ>(pts);
XYZ meanPt;
List <XYZ> orderedEigenvectors;
BestFitLine.PrincipalComponentsAnalysis(ptList, out meanPt, out orderedEigenvectors);
var normal = orderedEigenvectors[0].CrossProduct(orderedEigenvectors[1]);
var plane = dynRevitSettings.Doc.Application.Application.Create.NewPlane(normal, meanPt);
// take first 3 pts to form simplified normal
var bma = ptList[1] - ptList[0];
var cma = ptList[2] - ptList[0];
var simplifiedNorm = bma.CrossProduct(cma);
// find sign of normal that maximizes the dot product pca normal and simplfied normal
var dotProd = simplifiedNorm.DotProduct(normal);
if (dotProd < 0)
{
normal = -1 * normal;
}
outPuts[_planePort] = Value.NewContainer(plane);
outPuts[_normalPort] = Value.NewContainer(normal);
outPuts[_originPort] = Value.NewContainer(meanPt);
}