在AutoCAD中获取实体的子实体顶点答案

【问题标题】：Getting subentity vertex points of solid in AutoCAD在AutoCAD中获取实体的子实体顶点
【发布时间】：2017-07-25 16:01:46
【问题描述】：

我正在尝试查找扫掠折线的顶点。所以我有一个实体，它是通过沿着 3D 折线扫过一个圆来创建的。看起来是这样的：image of sweeped solid

上周整个星期五都在谷歌上搜索，我想我必须玩弄子实体部分。例如，我发现了如何更改子实体边缘的颜色，但看在上帝的份上，我找不到如何访问几何

这是我迄今为止尝试过的，但正如我在底部所指出的那样，我有点迷路了：

    [CommandMethod("SubEntExample")]
    public void SubEntExample()
    {
        Document doc = Application.DocumentManager.MdiActiveDocument;
        Database db = doc.Database;
        Editor ed = doc.Editor;

        PromptEntityOptions peo = new PromptEntityOptions("\nSelect a 3D solid: ");
        peo.SetRejectMessage("\nInvalid selection...");
        peo.AddAllowedClass(typeof(Solid3d), true);

        PromptEntityResult per = ed.GetEntity(peo);

        if (per.Status != PromptStatus.OK)
            return;

        using (Transaction Tx = db.TransactionManager.StartTransaction())
        {
            Solid3d solid = Tx.GetObject(per.ObjectId, OpenMode.ForWrite) as Solid3d;

            ObjectId[] ids = new ObjectId[] { per.ObjectId };

            FullSubentityPath path = new FullSubentityPath(ids, new SubentityId(SubentityType.Null, IntPtr.Zero));

            List<SubentityId> subEntIds = new List<SubentityId>();

            using (Autodesk.AutoCAD.BoundaryRepresentation.Brep brep =
                new Autodesk.AutoCAD.BoundaryRepresentation.Brep(path))
            {                    
                foreach (Autodesk.AutoCAD.BoundaryRepresentation.Edge edge in brep.Edges)
                {
                    subEntIds.Add(edge.SubentityPath.SubentId);
                }                    
            }

            foreach (SubentityId subentId in subEntIds)
            {

                *** here i am lost ***

            }
            Tx.Commit();
        }
    }

【问题讨论】：

如何将实体导出到 DXF 并查看文本文件中数据的构成？它可能会向您解释子实体的机制。我对手头的案例没有具体的了解，但是，如果它们是“id”，那么接下来你会“打开”那些 id 的什么？这些将返回提供坐标数据的合适对象。但这是一个猜测。查看 DXF 可能会显示更多信息。也许您可以将其添加到您的问题中。

标签： c# autocad

【解决方案1】：

我的第一个解决方案涉及获取所有信息并决定哪些是相关的，但感谢互联网的一些帮助 (:)) 我想出了一个更好的解决方案

    /// <summary>
    /// Checks if there are boundaryreps that are marked as elliptical or circular arcs
    /// returns true if we found at least 2 of those points
    /// also stores the points in a referenced Point3dCollection
    /// </summary>
    /// <param name="solid"></param>
    /// <param name="pts"></param>
    /// <returns></returns>
    private bool GetSweepPathPoints(Solid3d solid, ref Point3dCollection pts)
    {
        // create boundary rep for the solid
        using (Brep brep = new Brep(solid))
        {
            // get edges of the boundary rep
            BrepEdgeCollection edges = brep.Edges;
            foreach (Edge edge in edges)
            {
                // get the nativ curve geometry of the edges and then 
                // check if it is a circle
                // for more info look at:
                // http://adndevblog.typepad.com/autocad/2012/08/retrieving-native-curve-geometry-using-brep-api.html
                Curve3d curv = ((ExternalCurve3d)edge.Curve).NativeCurve;
                if (curv is CircularArc3d)
                {
                    // transform curved arch into circle and add it to the colecction 
                    // (if not in it alreadz)
                    CircularArc3d circle = curv as CircularArc3d;
                    if (!pts.Contains(circle.Center)) pts.Add(circle.Center);
                }
            }
        }
        return (pts.Count > 1) ? true : false;
    }

那我就这样称呼整个事情

            Point3dCollection pts = new Point3dCollection();
            // only do the whole thing if we face a swept solid
            if (GetSweepPathPoints(sld, ref pts))
            {
                for (int i = 0; i < pts.Count; i++)
                {
                    ed.WriteMessage("\nPt[{0}] = {1}", i, pts[i]);
                }
            }

【讨论】：