如何在Autodesk Revit各视图类型中选择所有被剖切元素？

Revit API没有直接提供获取“被剖切元素”的属性，需通过元素几何边界与视图剖切平面的相交关系来判断，以下是实现思路和代码：

核心逻辑 #

1. 根据视图类型（平面、剖面、立面、三维）提取对应的剖切平面
2. 过滤视图中可被剖切的元素（排除注释、标记等非实体类元素）
3. 检查元素的外包络盒是否被剖切平面贯穿，以此判断是否被剖切

C# 代码实现 #

using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using System.Collections.Generic;
using System.Linq;

public class GetSectionedElementsCommand : IExternalCommand
{
    public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
    {
        UIDocument uidoc = commandData.Application.ActiveUIDocument;
        Document doc = uidoc.Document;
        View activeView = uidoc.ActiveView;

        // 获取当前视图的剖切平面
        Plane sectionPlane = GetViewSectionPlane(activeView, doc);
        if (sectionPlane == null)
        {
            message = "当前视图无有效剖切平面";
            return Result.Failed;
        }

        // 收集视图中可被剖切的元素
        FilteredElementCollector collector = new FilteredElementCollector(doc, activeView.Id)
            .WhereElementIsNotElementType()
            .Where(e => e.Category != null && !IsNonSectionableCategory(e.Category.Id));

        List<Element> sectionedElements = new List<Element>();

        foreach (Element elem in collector)
        {
            BoundingBoxXYZ bbox = elem.get_BoundingBox(activeView);
            if (bbox == null) continue;

            // 判断元素外包络盒是否被剖切平面切割
            if (IsBoundingBoxSectioned(bbox, sectionPlane))
            {
                sectionedElements.Add(elem);
            }
        }

        // 选中识别出的被剖切元素
        uidoc.Selection.SetElementIds(sectionedElements.Select(e => e.Id).ToList());
        TaskDialog.Show("识别结果", $"共找到{sectionedElements.Count}个被剖切元素");

        return Result.Succeeded;
    }

    // 根据视图类型获取剖切平面
    private Plane GetViewSectionPlane(View view, Document doc)
    {
        // 处理平面图/天花板视图
        if (view is ViewPlan planView)
        {
            Level level = doc.GetElement(planView.GenLevelId) as Level;
            return level != null ? Plane.CreateByNormalAndOrigin(XYZ.BasisZ, new XYZ(0, 0, level.Elevation)) : null;
        }
        // 处理剖面图/立面图
        else if (view is ViewSection sectionView)
        {
            return sectionView.GetSectionPlane();
        }
        // 处理三维视图（含剖面盒的情况）
        else if (view is View3D view3D)
        {
            if (view3D.IsSectionBoxActive)
            {
                BoundingBoxXYZ sectionBox = view3D.GetSectionBox();
                // 取剖面盒的前侧平面作为判断基准，可按需调整
                return Plane.CreateByThreePoints(
                    sectionBox.Min,
                    new XYZ(sectionBox.Max.X, sectionBox.Min.Y, sectionBox.Min.Z),
                    new XYZ(sectionBox.Min.X, sectionBox.Max.Y, sectionBox.Min.Z)
                );
            }
            // 普通三维视图默认取XY平面，可自定义判断逻辑
            return Plane.CreateByNormalAndOrigin(XYZ.BasisZ, XYZ.Zero);
        }
        return null;
    }

    // 判断元素类别是否不可被剖切
    private bool IsNonSectionableCategory(ElementId categoryId)
    {
        List<ElementId> nonSectionableIds = new List<ElementId>
        {
            new ElementId(BuiltInCategory.OST_Annotations),
            new ElementId(BuiltInCategory.OST_TextNotes),
            new ElementId(BuiltInCategory.OST_Dimensions),
            new ElementId(BuiltInCategory.OST_Tags),
            new ElementId(BuiltInCategory.OST_Levels),
            new ElementId(BuiltInCategory.OST_Grids)
        };
        return nonSectionableIds.Contains(categoryId);
    }

    // 检查外包络盒是否被剖切平面贯穿
    private bool IsBoundingBoxSectioned(BoundingBoxXYZ bbox, Plane sectionPlane)
    {
        // 提取外包络盒的8个顶点
        List<XYZ> corners = new List<XYZ>
        {
            bbox.Min,
            new XYZ(bbox.Max.X, bbox.Min.Y, bbox.Min.Z),
            new XYZ(bbox.Min.X, bbox.Max.Y, bbox.Min.Z),
            new XYZ(bbox.Max.X, bbox.Max.Y, bbox.Min.Z),
            new XYZ(bbox.Min.X, bbox.Min.Y, bbox.Max.Z),
            new XYZ(bbox.Max.X, bbox.Min.Y, bbox.Max.Z),
            new XYZ(bbox.Min.X, bbox.Max.Y, bbox.Max.Z),
            bbox.Max
        };

        bool hasPositiveSide = false;
        bool hasNegativeSide = false;
        double tolerance = 1e-6; // 浮点运算容差

        foreach (XYZ corner in corners)
        {
            double dist = sectionPlane.SignedDistanceTo(corner);
            if (dist > tolerance)
                hasPositiveSide = true;
            else if (dist < -tolerance)
                hasNegativeSide = true;

            if (hasPositiveSide && hasNegativeSide)
                return true;
        }

        return false;
    }
}

补充说明 #

• 代码通过外包络盒判断存在一定误差，若需精确判断复杂几何元素，可替换为解析元素的实际几何图形（调用elem.get_Geometry(new Options())）
• 三维视图的剖切逻辑可根据需求调整（例如检查剖面盒的多个平面）
• 可按需扩展IsNonSectionableCategory方法中的排除类别，适配项目需求

内容的提问来源于stack exchange，提问作者DaveGrohl