I’m trying to return three familyInstances by MulitReturn and I’m getting only one of them. I have also tried just creating them in this method by FamilyInstance.ByCoordinates without returning any, and result was pretty much the same, only one output. Right now I made workaround by splitting this method to 3 separate, but I would like to know why it didnt work. Here is the code:
A bit of a guess but its probably Dynamo’s element binding when you call the FamilyInstance.ByCoordinates method. Each anonymous call deletes the last element from the document, so only the last family instance you create is output and all of them are pointing to the same memory address, which may explain why only 1 seemingly gets output. One way to check would be to assign each instance to a variable and pass these into your dictionary value keys.
Ideally though you should avoid calls to Dynamos libraries completely as its adding an unnecessary overhead to your program and gives you no control over say, element binding and the vast array of methods available in the Revit API.
I have tried returning it as variable before:
@Thomas_Mahon Following your advice I re-wrote the code. It took me whole day to learn basics of Revit API library, but I think it was worth it. From here I would like to recommend this Lab, it covered almost everything what I needed to write this. I’m also leaving here the code.
//Create plate sections
[MultiReturn(new[] { "BaseFamilyinstance", "NegativeFamilyInstance", "PositiveFamilyInstance" })]
public static Dictionary<string,object> CreatePlateSection(double negativeDistance,double positiveDistance)
{
//Set document as current document
Document document = RevitServices.Persistence.DocumentManager.Instance.CurrentDBDocument;
//Collect FamilySymbols
var symbolCollector = new FilteredElementCollector(document)
.OfClass(typeof(FamilySymbol));
//Get BaseSection FamilySymbol
FamilySymbol baseSectionSymbol = symbolCollector
.Where(x => ((FamilySymbol)x).Name.Equals("BaseSection"))
.Cast<FamilySymbol>()
.FirstOrDefault();
//Get NegativeSection FamilySymbol
FamilySymbol negativeSectionSymbol = symbolCollector
.Where(x => ((FamilySymbol)x).Name.Equals("NegativeSection"))
.Cast<FamilySymbol>()
.FirstOrDefault();
//Get PositiveSection FamilySymbol
FamilySymbol positiveSectionSymbol = symbolCollector
.Where(x => ((FamilySymbol)x).Name.Equals("PositiveSection"))
.Cast<FamilySymbol>()
.FirstOrDefault();
//Get BaseSection plate and cornice height
double baseHeight = baseSectionSymbol.LookupParameter("Wysokość").AsDouble();
double baseCorniceHeight = baseSectionSymbol.LookupParameter("Wysokość gzymsu nad płytą").AsDouble();
//Calculate NegativeSection plate and cornice height
double negativeHeight = baseHeight - Math.Abs(mmToFeet(negativeDistance)) * 0.02;
double negativeCorniceHeight = baseCorniceHeight + Math.Abs(mmToFeet(negativeDistance)) * 0.02;
//Calculate PositiveSection plate and cornive height
double positiveHeight = baseHeight - Math.Abs(mmToFeet(positiveDistance)) * 0.02;
double positiveCorniceHeight = baseCorniceHeight + Math.Abs(mmToFeet(positiveDistance)) * 0.02;
//Insert location of BaseSection
XYZ pointBaseSection = new XYZ(0, 0, 0);
//Insert location of NegativeSection
XYZ pointNagativeSection = new XYZ(0,mmToFeet(negativeDistance),0);
//Insert location of PositiveSection
XYZ pointPositiveSection = new XYZ(0,mmToFeet(positiveDistance),0);
//Create new transaction
using (Transaction transaction = new Transaction(document,"Create BaseSEction"))
{
transaction.Start();
//Change NegativeSection FamilySymbol parameters
negativeSectionSymbol.LookupParameter("Wysokość").Set(negativeHeight);
negativeSectionSymbol.LookupParameter("Wysokość gzymsu nad płytą").Set(negativeCorniceHeight);
//Change PositiveSection FamilySymbol parameters
positiveSectionSymbol.LookupParameter("Wysokość").Set(positiveHeight);
positiveSectionSymbol.LookupParameter("Wysokość gzymsu nad płytą").Set(positiveCorniceHeight);
//Create BaseSection FamilyInstance
FamilyInstance baseSectionFamilyInstance = document.FamilyCreate
.NewFamilyInstance(pointBaseSection, baseSectionSymbol, Autodesk.Revit.DB.Structure.StructuralType.UnknownFraming);
//Create NegativeSection FamilyInstance
FamilyInstance negativeSectionFamilyInstance = document.FamilyCreate
.NewFamilyInstance(pointNagativeSection, negativeSectionSymbol, Autodesk.Revit.DB.Structure.StructuralType.UnknownFraming);
//Create PositiveSection FamilyInstance
FamilyInstance positiveSectionFamilyInstance = document.FamilyCreate
.NewFamilyInstance(pointPositiveSection, positiveSectionSymbol, Autodesk.Revit.DB.Structure.StructuralType.UnknownFraming);
transaction.Commit();
//Retrun FamilyInstances
return new Dictionary<string, object>
{
{ "BaseFamilyinstance", baseSectionFamilyInstance},
{ "NegativeFamilyInstance", negativeSectionFamilyInstance },
{ "PositiveFamilyInstance", positiveSectionFamilyInstance }
};
}
}
