need help for creating auto dimension setting between grid and duct/pipes

[esthervinitha]

I am developing a revit plugin for the first time in C# for auto dimension setting between grid and duct/pipes... I got an error in which I cannot convert Autodesk.Revit.DB.Curve to Autodesk.Revit.DB.XYZ 

The code below:

u

{ 

[Transaction(TransactionMode.Manual)] 

    public class Dim : IExternalCommand 

{               

  public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements) 

      {               

  Document doc = commandData.Application.ActiveUIDocument.Document;           

            View activeView = doc.ActiveView;              

 FilteredElementCollector collector = new FilteredElementCollector(doc, activeView.Id);          

      var ductAndChwElements = collector.OfCategory(BuiltInCategory.OST_DuctCurves).UnionWith(collector.OfCategory(BuiltInCategory.OST_PipeCurves)).WhereElementIsNotElementType().ToElements();                 

 var coreWalls = new FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Walls).WhereElementIsNotElementType();                           coreWalls.Where(e => e.Name.ToLower().Contains("Core"));         

     var gridLines = new FilteredElementCollector(doc).OfCategory(BuiltInCategory.OST_Grids).WhereElementIsNotElementType();      

       using (Transaction t = new Transaction(doc, "set out Dimensions"))               

   {                   

    t.Start();          

          foreach (Element element in ductAndChwElements)             

      {                      

       LocationCurve curve = element.Location as LocationCurve;   

                                                 if (curve != null) 

                             {                                

   Reference nearestRef = FindNearestReference(doc, curve.Curve, coreWalls, gridLines);    

      if (nearestRef != null)  

 {                                   

              XYZ elementPoint = curve.Curve.GetEndPoint(0);                              

    XYZ refPoint = nearestRef.GlobalPoint;                                  

   Line dimensionLine = Line.CreateBound(elementPoint, refPoint);                                  

      ReferenceArray ra = new ReferenceArray();                                    

 ra.Append(nearestRef);                                 

     ra.Append(new Reference(element));                                   

 doc.Create.NewDimension(activeView, dimensionLine, ra);                            

       }

          }                      

 }                     

  t.Commit();           

  }                

 return Result.Succeeded;          

  }          

 private Reference FindNearestReference(Document doc, Curve curve1,FilteredElementCollector coreWalls, FilteredElementCollector gridLines)       {                

 Reference nearestRef = null;             

 double minDistance = double.MaxValue;                

 foreach (Element Wall in coreWalls)          

   {                      

 LocationCurve wallCurve = Wall.Location as LocationCurve;                   

             if (wallCurve != null)      

              {                       

     double distance = curve1.Distance(wallCurve.Curve);                          

             if (distance < minDistance)                       

    {                                 

  nearestRef = new Reference(Wall);                               

  minDistance = distance;                        

 }                   

    }              

   }               

  foreach (Element grid in gridLines)          

   {                       

Curve gridCurve = (grid.Location as LocationCurve).Curve;                  

   if (gridCurve != null)                  

  {                         

 double distance = curve1.Distance(gridCurve);                            

  if (distance < minDistance)                          

 {                                

   nearestRef = new Reference(grid);                                 

minDistance = distance;                       

  }                      

 }                

 }                

 return nearestRef;          

  }          

[jeremy_tammik · Accepted solution]

Dear Esther, 

Thank you for raising the issue here after our email conversation. Your code would be more readable if you format it as code using the </> Insert/Edit code sample button above. Also, it is rather long. I do not see off-hand where the conversion might be that is causing an issue for you. Furthermore, there is a discrepancy between your title and the text; in the title, you talk about creating dimensioning, which is a pretty high-level question; the text only mentions a very low-level question on extracting a 3D XYZ point or vector from a curve.

To address the latter: you cannot convert a curve to an XYZ point, because they are different things. You could easily extract an infinite number of XYZ points or vectors from a curve, however. For instance, you could query the start, mid and endpoints, or any point or tangent vector along the curve.

I hope this helps clarify and move forward.

Best regards,

Jeremy