Revit API获取几何信息 - 墙的底面面积

通过element.get_Geometry(opt);可以获取对象的几何信息。
参数Option指定参数的限制条件，比如详细程度，哪个视图。
获得的几何信息保存在一个数组中，可以通过遍历得到点，面等信息。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using WinForm = System.Windows.Forms;

using Autodesk.Revit.UI;
using Autodesk.Revit.DB;
using Autodesk.Revit.Attributes;

using Autodesk.Revit.DB.Mechanical;
using Autodesk.Revit.UI.Selection;
using Autodesk.Revit.ApplicationServices;

using Autodesk.Revit.DB.Structure;

using System.Xml;

namespace RevitCodes
{
    [TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class GetWallBFace : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string messages, ElementSet elements)
        {

            UIApplication app = commandData.Application;
            Document doc = app.ActiveUIDocument.Document;

            //select a wall      
            Reference ref1 = app.ActiveUIDocument.Selection.PickObject(Autodesk.Revit.UI.Selection.ObjectType.Element, "Please pick a wall");
            Element elem = doc.GetElement(ref1);
            Wall wall = elem as Wall;

            Options opt = new Options();
            opt.ComputeReferences = true;
            opt.DetailLevel = Autodesk.Revit.DB.DetailLevels.Medium;

            GeometryElement e = wall.get_Geometry(opt);

            foreach (GeometryObject obj in e.Objects)
            {
                Solid solid = obj as Solid;
                if (solid != null && solid.Faces.Size > 0)
                    FindBottomFace(solid);
            }

            return Result.Succeeded;
        }

        Face FindBottomFace(Solid solid)
        {
            PlanarFace pf = null;
            foreach (Face face in solid.Faces)
            {
                pf = face as PlanarFace;
                if (null != pf)
                {
                    if (Math.Abs(pf.Normal.X) < 0.01 && Math.Abs(pf.Normal.Y) < 0.01 && pf.Normal.Z < 0)
                    {
                        TaskDialog.Show("Wall Bottom Face", "Area is " + pf.Area.ToString() + "; Origin = (" + pf.Origin.X.ToString() + "  " + pf.Origin.Y.ToString() + "  " + pf.Origin.Z.ToString() + ")");

                        break;
                    }
                }
            }
            return pf;
        }

    }


    [TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class GetColumnBottomFace : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string messages, ElementSet elements)
        {

            UIApplication app = commandData.Application;
            Document doc = app.ActiveUIDocument.Document;

            //select a column      
            Reference ref1 = app.ActiveUIDocument.Selection.PickObject(Autodesk.Revit.UI.Selection.ObjectType.Element, "Please pick a column");
            Element elem = doc.GetElement(ref1);
            FamilyInstance column = elem as FamilyInstance;

            Options opt = new Options();
            opt.ComputeReferences = true;
            opt.DetailLevel = Autodesk.Revit.DB.DetailLevels.Medium;

            GeometryElement e = column.get_Geometry(opt);

            foreach (GeometryObject obj in e.Objects)
            {

                if (obj is Solid)
                {
                    Solid solid = obj as Solid;
                    FindBottomFace(solid);
                }
                else if (obj is GeometryInstance)
                {
                    GeometryInstance geoInstance = obj as GeometryInstance;
                    GeometryElement geoElement = geoInstance.GetInstanceGeometry();
                    foreach (GeometryObject obj2 in geoElement.Objects)
                    {
                        if (obj2 is Solid)
                        {
                            Solid solid2 = obj2 as Solid;
                            if (solid2.Faces.Size > 0)
                                FindBottomFace(solid2);
                        }
                    }
                }
            }
            return Result.Succeeded;
        }

        Face FindBottomFace(Solid solid)
        {
            PlanarFace pf = null;
            foreach (Face face in solid.Faces)
            {
                pf = face as PlanarFace;
                if (null != pf)
                {
                    if (Math.Abs(pf.Normal.X) < 0.01 && Math.Abs(pf.Normal.Y) < 0.01 && pf.Normal.Z < 0)
                    {
                        TaskDialog.Show("column Bottom Face", "Area is " + pf.Area.ToString() + "; Origin = (" + pf.Origin.X.ToString() + "  " + pf.Origin.Y.ToString() + "  " + pf.Origin.Z.ToString() + ")");

                        break;
                    }
                }
            }
            return pf;
        }

    }

    [TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    public class GetWallBottomFace : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string messages, ElementSet elements)
        {
            UIApplication app = commandData.Application;
            Document doc = app.ActiveUIDocument.Document;

            //select a wall
            Reference ref1 = app.ActiveUIDocument.Selection.PickObject(Autodesk.Revit.UI.Selection.ObjectType.Element, "Pick a wall");
            Element elem = doc.GetElement(ref1);
            Wall wall = elem as Wall;

            Options opt = new Options();
            opt.ComputeReferences = true;
            opt.DetailLevel = Autodesk.Revit.DB.DetailLevels.Medium;

            GeometryElement e = wall.get_Geometry(opt);
            foreach (GeometryObject obj in e.Objects)
            {
                Solid solid = obj as Solid;
                if (solid != null && solid.Faces.Size > 0)
                {
                    FindBottomFaces(solid);
                }
            }

            return Result.Succeeded;
        }

        Face FindBottomFaces(Solid solid)
        {
            PlanarFace pf = null;
            foreach (Face face in solid.Faces)
            {
                pf = face as PlanarFace;
                if (null != pf)
                {
                    if (Math.Abs(pf.Normal.X) < 0.01 && Math.Abs(pf.Normal.Y) < 0.01 && pf.Normal.Z < 0)
                    {
                        TaskDialog.Show("the bottom face's area is ", pf.Area.ToString());
                    }
                }
            }
            return pf;
        }
    }
}

from:http://revit.5d6d.com/thread-1285-1-1.html