几何实体的创建方法之一:
构成封闭底面,指定拉伸方向与拉伸高度。GeometryCreationUtilities
//自创几何实体相交法
[TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
public class FindIntersectWallsByGeometry : IExternalCommand
{    
public Result Execute(ExternalCommandData 
commandData, 
ref string messages, ElementSet elements)
    {
        UIApplication app = commandData.Application;
        Document doc = app.ActiveUIDocument.Document;
        Transaction trans = 
new Transaction(doc, 
"ExComm");
        trans.Start();        
//pick a point to draw solid在屏幕上选择一点,找到附近的墙。
        Selection sel = app.ActiveUIDocument.Selection;
        XYZ pt = sel.PickPoint(
"Please pick a point to get the close walls");        
//XYZ pttemp1 = sel.PickPoint(Autodesk.Revit.UI.Selection.ObjectSnapTypes.None, "Pick leader end...");
        //XYZ pttemp2 = sel.PickPoint(Autodesk.Revit.UI.Selection.ObjectSnapTypes.None, "Pick leader elbow...");
        //
        double dBoxLength = 
3;        
//Z值不变,以选择的点为中心,找到矩形四个点。
        XYZ pt1 = 
new XYZ(pt.X - dBoxLength / 
2, pt.Y - dBoxLength / 
2, pt.Z);
        XYZ pt2 = 
new XYZ(pt.X + dBoxLength / 
2, pt.Y - dBoxLength / 
2, pt.Z);
        XYZ pt3 = 
new XYZ(pt.X + dBoxLength / 
2, pt.Y + dBoxLength / 
2, pt.Z);
        XYZ pt4 = 
new XYZ(pt.X - dBoxLength / 
2, pt.Y + dBoxLength / 
2, pt.Z);        
//创建四条线。
        Line lineBottom = app.Application.Create.NewLineBound(pt1, pt2);
        Line lineRight = app.Application.Create.NewLineBound(pt2, pt3);
        Line lineTop = app.Application.Create.NewLineBound(pt3, pt4);
        Line lineLeft = app.Application.Create.NewLineBound(pt4, pt1);        
//封闭曲线
        CurveLoop profile = 
new CurveLoop();
        profile.Append(lineBottom);
        profile.Append(lineRight);
        profile.Append(lineTop);
        profile.Append(lineLeft);
        List<CurveLoop> loops = 
new List<CurveLoop>();
        loops.Add(profile);        
//创建实体的方法(底面,拉伸方向,拉伸高度)
        XYZ vector = 
new XYZ(
0, 
0, 
1);
        Solid solid = GeometryCreationUtilities.CreateExtrusionGeometry(loops, vector, 
10);        
//相交过滤器
        FilteredElementCollector collector = 
new FilteredElementCollector(doc);
        ElementIntersectsSolidFilter solidFilter = 
new ElementIntersectsSolidFilter(solid);
        collector.WherePasses(solidFilter);
        sel.Elements.Clear();        
//Add these interseting element to the selection
        foreach (Element elem 
in collector)
        {
            sel.Elements.Add(elem);
        }
        trans.Commit();        
return Result.Succeeded;
    }
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