Cut wall make error

[sonicer]

Does someone know where is problem...

need cut wall with family void. But only if the results change the volume of the wall.

public void test(Document doc, IEnumerable<Element> w, IEnumerable<Element> e, ProgressBar pr)
        {


            double volumebefore;
            double volumeafter;

            foreach (Element q in w)
            {

                volumebefore = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();
                foreach (Element s in e)
                {

                    try
                    {
                        using (Transaction tx = new Transaction(doc))
                        {
                            tx.Start("start transaction");
                            if (InstanceVoidCutUtils.CanBeCutWithVoid(q))
                            {
                                InstanceVoidCutUtils.AddInstanceVoidCut(doc, q, s);
                            }
                            // ElementIntersectsElementFilter cutintersectsfilter = new ElementIntersectsElementFilter(s, false);
                            // bool FamilyIntersectsWall = cutintersectsfilter.PassesFilter(doc, q.Id);
                            // if (FamilyIntersectsWall)


                            tx.Commit();
                            
                          
                                using (Transaction t1 = new Transaction(doc))
                                {
                                    t1.Start("start ");

                                    volumeafter = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();


                                    if (volumebefore == volumeafter)
                                    {

                                        InstanceVoidCutUtils.RemoveInstanceVoidCut(doc, q, s);

                                    }
                                    else
                                    {
                                        volumebefore = volumeafter;
                                    }
                                    t1.Commit();
                                }
                            }
                            
                        }
                    }

                    catch { }



                    pr.Increment(1);
                }
            }
        }

still make error

The iterator cannot proceed due to changes made to the Element table in Revit's database (typically, this can be the result of an Element deletion).

[FAIR59]

I think, based on the error text you provided, that you pass a null value in list of walls or in the list of cutters. That can be solved by some error checking at the beginning of the method.

foreach (Element q in w)
            {
		if (q == null || !q.IsValidObject) continue;
		if (!InstanceVoidCutUtils.CanBeCutWithVoid(q)) continue;
                volumebefore = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();
                foreach (Element s in e)
                {
                    if ( s ==null || !s.IsValidObject) continue;
                    if ( InstanceVoidCutUtils.InstanceVoidCutExists(q,s)) continue;
                    try
                    {
                        using (Transaction tx = new Transaction(doc))
                        {
                            tx.Start("start transaction");
                            InstanceVoidCutUtils.AddInstanceVoidCut(doc, q, s);
       			    tx.Commit();
			}

That will solve the issue, but leaves the question why it occurs.

Suggestions:

• Are you creating the cutters in the same command?  If so, is the FamilySymbol Active?
• try a document.Regenerate() before calling the method.

[sonicer]

dont know where is problem ...if I cut the wall and then check if the volume is changing then I give same volume as before cut...

I used also doc.regenerate().

[FAIR59]

Can you make the cut manually using the same cutting family?

If that's true, then I think the problem is somewhere in the rest of your code.

Using the same layout I made a command (Revit 2016) that works. { select 1 or more walls, 1 or more cutting instances and run command}

    [Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class Cmd_CutWalls : IExternalCommand
    {
        StringBuilder sb = new StringBuilder();
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            UIDocument uiDoc = commandData.Application.ActiveUIDocument;
            Document doc = uiDoc.Document;
            Autodesk.Revit.UI.Selection.Selection sel = commandData.Application.ActiveUIDocument.Selection;
            List<Element> walls = new List<Element>();
            List<Element> cutters = new List<Element>();
            foreach (ElementId id in sel.GetElementIds())
            {
                Element e = doc.GetElement(id);
                if (e is Wall) { walls.Add(e);}
                else { cutters.Add(e); }
            }

            double volumebefore = 0;
            double volumeafter =0 ;

            using (TransactionGroup tg = new TransactionGroup(doc, "cut walls"))
            {
                tg.Start();
                foreach (Element q in walls)
                {
                    if (q == null || !q.IsValidObject) continue;
                    sb.AppendLine(string.Format("wall  {0}", q.Id));
                    if (!InstanceVoidCutUtils.CanBeCutWithVoid(q)) continue;
                    volumebefore = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();
                    foreach (Element s in cutters)
                    {
                        if (s == null || !s.IsValidObject) continue;
                        if (!InstanceVoidCutUtils.IsVoidInstanceCuttingElement(s))
                        {
                            sb.AppendLine("      instance is not family with unattached voids for cutting");
                            continue;
                        }
                        sb.AppendLine(string.Format("   cutter  {0}", s.Id));
                        if (InstanceVoidCutUtils.InstanceVoidCutExists(q, s))
                        {
                            sb.AppendLine("      instance is already cutting wall");
                            continue;
                        }
                        try
                        {
                            using (Transaction tx = new Transaction(doc))
                            {
                                tx.Start("start transaction");
                                InstanceVoidCutUtils.AddInstanceVoidCut(doc, q, s);
                                tx.Commit();
                            }
                            using (Transaction t1 = new Transaction(doc))
                            {
                                t1.Start("start ");
                                volumeafter = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();
                                sb.AppendLine(string.Format("      volume_before: {0}    volume_after: {1}", volumebefore, volumeafter));
                                if (Math.Abs(volumebefore - volumeafter) < 0.0001)
                                {
                                    InstanceVoidCutUtils.RemoveInstanceVoidCut(doc, q, s);
                                    sb.AppendLine("        not cutting, cut removed");
                                }
                                else
                                {
                                    volumebefore = volumeafter;
                                    sb.AppendLine("        cut succeeded");
                                }
                                t1.Commit();
                            }
                        }
                        catch (Exception ex)
                        {
                            TaskDialog.Show("catch", ex.ToString());
                            return Result.Failed;
                        }
                    }
                    sb.AppendLine();
                }
                tg.Assimilate();
            }
            TaskDialog.Show("debug", sb.ToString());
            return Result.Succeeded;
        }
    }

[sonicer · Accepted solution]

i found a problem ..

my mistake.

volumebefore = q.get_Parameter(BuiltInParameter.HOST_AREA_COMPUTED).AsDouble();

change to 

volumebefore = q.get_Parameter(BuiltInParameter.HOST_VOLUME_COMPUTED).AsDouble();