Rotating Elements on their axis

[recepagah12]

I am trying to create an add-in. Rotate multiple elements with their own axis. 

But element rotates angle increasing within foreach loop. I even tried constant value by ignoring user input.

The rotation angle increasing by applied elements.

double  RotateAngle;

            using (Rotating_Form thisForm = new Rotating_Form())
            {
                // Determine the position of form
                thisForm.StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
                // Show the form 
                thisForm.ShowDialog();

                // Convert Radian to Degree
                RotateAngle = thisForm.Get_Angle()*Math.PI/180;

                if (thisForm.DialogResult == System.Windows.Forms.DialogResult.Cancel)
                {
                    return Result.Cancelled;
                }
                using (Transaction t = new Transaction(doc))
                {
                    //Provide access to make change in document
                    t.Start("Rotate Element");
                    // Collect selected elements
                    ElementSet selection = new ElementSet();
                    //  Select element references
                    ICollection<ElementId> selectedIds = uidoc.Selection.GetElementIds();

                    foreach (ElementId elementId in selectedIds)
                    {
                        selection.Insert(uidoc.Document.GetElement(elementId));
                        foreach (Element e in selection)
                        {
                            //Get the location curve
                            Location location = e.Location;
                            LocationCurve locationCurve = location as LocationCurve;
                            Curve curve = locationCurve.Curve;

                            // Get the end point of curve
                            XYZ point1 = curve.GetEndPoint(0);
                            XYZ point2 = curve.GetEndPoint(1);
                            // Get the mid point of curve
                            XYZ midPoint = (point1 + point2) / 2;
                            XYZ midHigh = midPoint.Add(XYZ.BasisZ);
                            Line axisLine = Line.CreateBound(midPoint, midHigh);

                            //Rotate elements on their axis
                            bool rotated = locationCurve.Rotate(axisLine, RotateAngle);
                            rotated = true;
                        }
                    }
                    // Nothings selected
                    if (selection.IsEmpty)
                    {
                        message = "Please select at least one element";
                        return Result.Failed;
                    }

                    t.Commit();
                }
            }

[BardiaJahan · Accepted solution]

I think the inner Foreach loop is redundant. For each selected element, you would need to retrieve the location curve and rotate it - the is only one Foreach. Your current snippet keeps adding elements to ElementSet selection, which means the first element is rotated once, the second element is rotated twice, etc.

Try:

foreach (ElementId elementId in selectedIds)
                {
                    Element e = doc.GetElement(elementId);

                    //Get the location curve
                    Location location = e.Location;
                    LocationCurve locationCurve = location as LocationCurve;
                    Curve curve = locationCurve.Curve;

                    // Get the end point of curve
                    XYZ point1 = curve.GetEndPoint(0);
                    XYZ point2 = curve.GetEndPoint(1);
                    // Get the mid point of curve
                    XYZ midPoint = (point1 + point2) / 2;
                    XYZ midHigh = midPoint.Add(XYZ.BasisZ);
                    Line axisLine = Line.CreateBound(midPoint, midHigh);

                    //Rotate elements on their axis
                    bool rotated = locationCurve.Rotate(axisLine, RotateAngle);
                    rotated = true;
                }

[recepagah12]

Thank you, I am appreciated to your help.