AutoCAD DevBlog

Creating PolyfaceMesh from a 3D Solid

By Balaji Ramamoorthy

Here is a sample code to create a Polyface Mesh from a 3D solid. Most of the code in this blog post is from Kean's blog post on a similar topic with some changes made to create a Polyface Mesh. As in the original post, I have tested it with a sphere and the mesh parameters may need tweaking for more complex solids.

using Autodesk.AutoCAD.BoundaryRepresentation;

 

[CommandMethod("SOL2POLYFACEMESH")]

static public void PolyfaceMeshFromSolid()

{

    Document doc =

    Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    PromptEntityOptions peo =

    new PromptEntityOptions("Select a 3D solid");

    peo.SetRejectMessage("\nA 3D solid must be selected.");

    peo.AddAllowedClass(typeof(Solid3d), true);

    PromptEntityResult per = ed.GetEntity(peo);

 

    if (per.Status != PromptStatus.OK)

        return;

 

    Transaction tr = db.TransactionManager.StartTransaction();

    using (tr)

    {

        BlockTable bt = (BlockTable)tr.GetObject

            (

                db.BlockTableId,

                OpenMode.ForRead,

                false

            );

 

        BlockTableRecord btr = (BlockTableRecord)

                tr.GetObject(

                                bt[BlockTableRecord.ModelSpace],

                                OpenMode.ForWrite, false

                            );

 

        Solid3d sol = tr.GetObject(

                                    per.ObjectId,

                                    OpenMode.ForRead

                                  ) as Solid3d;

 

        // Calculate the approximate size of our solid

        double length = sol.GeometricExtents.MinPoint.GetVectorTo

                        (sol.GeometricExtents.MaxPoint).Length;

 

        using (Brep brp = new Brep(sol))

        {

            // Create and set our mesh control object

 

            using (Mesh2dControl mc = new Mesh2dControl())

            {

                // These settings seem extreme, but only result

                // in ~500 faces for a sphere (during my testing,

                // anyway). Other control settings are available

 

                mc.MaxNodeSpacing = length / 10000;

                mc.MaxSubdivisions = 100000000;

 

                // Create a mesh filter object

 

                using (Mesh2dFilter mf = new Mesh2dFilter())

                {

                    // Use it to map our control settings

                    // to the Brep

 

                    mf.Insert(brp, mc);

 

                    // Generate a mesh using the filter

 

                    PolyFaceMesh pfm = new PolyFaceMesh();

                    pfm.SetDatabaseDefaults();

                    pfm.ColorIndex = 2;

                    btr.AppendEntity(pfm);

 

                    short v0 = 0;

                    short v1 = 0;

                    short v2 = 0;

                    short v3 = 0;

                    short v = 0;

 

                    Dictionary<Point3d, short> vertexLookup

                            = new Dictionary<Point3d, short>();

 

                    using (Mesh2d m = new Mesh2d(mf))

                    {

                        // Extract individual faces

                        // from the mesh data

 

                        foreach (Element2d e in m.Element2ds)

                        {

                            foreach (Node n in e.Nodes)

                            {

                                if (! vertexLookup.ContainsKey(n.Point))

                                {

                                    PolyFaceMeshVertex pfmVertex

                                        = new PolyFaceMeshVertex(n.Point);

 

                                    pfm.AppendVertex(pfmVertex);

                                    vertexLookup.Add(n.Point, ++v);

 

                                    tr.AddNewlyCreatedDBObject

                                            (pfmVertex, true);

                                }

 

                                n.Dispose();

                            }

                        }

 

                        foreach (Element2d e in m.Element2ds)

                        {

                            Point3dCollection pts

                                    = new Point3dCollection();

                            foreach (Node n in e.Nodes)

                            {

                                pts.Add(n.Point);

 

                                n.Dispose();

                            }

 

                            e.Dispose();

 

                            v0 = 0;

                            if (vertexLookup.ContainsKey(pts[0]))

                                v0 = vertexLookup[pts[0]];

 

                            v1 = 0;

                            if (vertexLookup.ContainsKey(pts[1]))

                                v1 = vertexLookup[pts[1]];

 

                            v2 = 0;

                            if (vertexLookup.ContainsKey(pts[2]))

                                v2 = vertexLookup[pts[2]];

 

                            v3 = 0;

                            if (pts.Count == 4)

                            {

                                if (vertexLookup.ContainsKey(pts[3]))

                                    v3 = vertexLookup[pts[3]];

                            }

 

                            FaceRecord fr

                               = new FaceRecord(v0, v1, v2, v3);

                            pfm.AppendFaceRecord(fr);

                            tr.AddNewlyCreatedDBObject(fr, true);

                        }

                    }

 

                    tr.AddNewlyCreatedDBObject(pfm, true);

 

                    vertexLookup.Clear();

                }

            }

        }

        tr.Commit();

    }

}

Here is a screenshot of the Polyface Mesh created from the sphere :

Publishing model views to a multi-sheet DWF/PDF

By Balaji Ramamoorthy

An approach to create a single multi-sheet PDF or DWF file that displays portions of your drawing as separate sheets is to create model views and get them published.

Here is a sample code to publish two model views named "Test1" and "Test2" as separate sheets in a multi-sheet DWF file.

using Autodesk.AutoCAD.PlottingServices;

using Autodesk.AutoCAD.Publishing;

 

[CommandMethod("PublishViews2MultiSheet")]

static public void PublishViews2MultiSheet()

{

    Document doc = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    StringCollection viewsToPlot = new StringCollection();

    viewsToPlot.Add("Test1");

    viewsToPlot.Add("Test2");

 

    // Create page setup based on the views

    using (Transaction Tx = db.TransactionManager.StartTransaction())

    {

        ObjectId layoutId = LayoutManager.Current.GetLayoutId

                        (LayoutManager.Current.CurrentLayout);

 

        Layout layout

            = Tx.GetObject(layoutId, OpenMode.ForWrite) as Layout;

 

        foreach (String viewName in viewsToPlot)

        {

            PlotSettings plotSettings

                           = new PlotSettings(layout.ModelType);

            plotSettings.CopyFrom(layout);

 

            PlotSettingsValidator psv

                                = PlotSettingsValidator.Current;

 

            psv.SetPlotConfigurationName

                (   plotSettings,

                    "DWF6 ePlot.pc3",

                    "ANSI_A_(8.50_x_11.00_Inches)"

                );

            psv.RefreshLists(plotSettings);

            psv.SetPlotViewName(plotSettings, viewName);

            psv.SetPlotType

                (

                    plotSettings,

                    PlotType.View

                );

            psv.SetUseStandardScale(plotSettings, true);

            psv.SetStdScaleType

                (

                    plotSettings,

                    StdScaleType.ScaleToFit

                );

            psv.SetPlotCentered(plotSettings, true);

            psv.SetPlotRotation

                (

                    plotSettings,

                    PlotRotation.Degrees000

                );

            psv.SetPlotPaperUnits

                (

                    plotSettings,

                    PlotPaperUnit.Inches

                );

 

            plotSettings.PlotSettingsName

                    = String.Format("{0}{1}", viewName, "PS");

            plotSettings.PrintLineweights = true;

            plotSettings.AddToPlotSettingsDictionary(db);

 

            Tx.AddNewlyCreatedDBObject(plotSettings, true);

            psv.RefreshLists(plotSettings);

 

            layout.CopyFrom(plotSettings);

        }

 

        Tx.Commit();

    }

 

    //put the plot in foreground

    short bgPlot = (short)Application.GetSystemVariable("BACKGROUNDPLOT");

    Application.SetSystemVariable("BACKGROUNDPLOT", 0);

 

    string dwgFileName

            = Application.GetSystemVariable("DWGNAME") as string;

    string dwgPath

        = Application.GetSystemVariable("DWGPREFIX") as string;

    using (Transaction Tx = db.TransactionManager.StartTransaction())

    {

        DsdEntryCollection collection = new DsdEntryCollection();

        ObjectId activeLayoutId

            = LayoutManager.Current.GetLayoutId

                        (LayoutManager.Current.CurrentLayout);

 

        foreach (String viewName in viewsToPlot)

        {

            Layout layout = Tx.GetObject(

                                            activeLayoutId,

                                            OpenMode.ForRead

                                        ) as Layout;

 

            DsdEntry entry = new DsdEntry();

 

            entry.DwgName = dwgPath + dwgFileName;

            entry.Layout = layout.LayoutName;

            entry.Title = viewName;

            entry.NpsSourceDwg = entry.DwgName;

            entry.Nps = String.Format("{0}{1}", viewName, "PS");

 

            collection.Add(entry);

        }

 

        // remove the ".dwg" extension

        dwgFileName = dwgFileName.Substring(0, dwgFileName.Length - 4);

 

        DsdData dsdData = new DsdData();

 

        dsdData.SheetType = SheetType.MultiDwf;

        dsdData.ProjectPath = dwgPath;

        dsdData.DestinationName

                = dsdData.ProjectPath + dwgFileName + ".dwf";

 

        if (System.IO.File.Exists(dsdData.DestinationName))

            System.IO.File.Delete(dsdData.DestinationName);

 

        dsdData.SetDsdEntryCollection(collection);

 

        string dsdFile

                = dsdData.ProjectPath + dwgFileName + ".dsd";

 

        //Workaround to avoid promp for pdf file name

        //set PromptForDwfName=FALSE in dsdData using StreamReader/StreamWriter

 

        dsdData.WriteDsd(dsdFile);

 

        System.IO.StreamReader sr = new System.IO.StreamReader(dsdFile);

        string str = sr.ReadToEnd();

        sr.Close();

 

        // Replace PromptForDwfName

        str = str.Replace("PromptForDwfName=TRUE", "PromptForDwfName=FALSE");

 

        // Workaround to have the page setup names included in the DSD file

        // Replace Setup names based on the created page setups

        // May not be required if Nps is output to the DSD

        int occ = 0;

        int index = str.IndexOf("Setup=");

        int startIndex = 0;

        StringBuilder dsdText = new StringBuilder();

        while(index != -1)

        {

            // 6 for length of "Setup="

            String str1 =

            str.Substring(startIndex, index + 6 - startIndex );

 

            dsdText.Append(str1);

            dsdText.Append(

                String.Format("{0}{1}", viewsToPlot[occ], "PS"));

 

            startIndex = index + 6;

            index = str.IndexOf("Setup=", index + 6);

 

            if (index == -1)

            {

                dsdText.Append(

               str.Substring(startIndex, str.Length-startIndex));

            }

            occ++;

        }

 

        // Write the DSD

        System.IO.StreamWriter sw

                        = new System.IO.StreamWriter(dsdFile);

        sw.Write( dsdText.ToString());

        sw.Close();

 

        // Read the updated DSD file

        dsdData.ReadDsd(dsdFile);

 

        // Erase DSD as it is no longer needed

        System.IO.File.Delete(dsdFile);

 

        PlotConfig plotConfig

            = PlotConfigManager.SetCurrentConfig("DWF6 ePlot.pc3");

 

        Publisher publisher = Application.Publisher;

 

        // Publish it

        publisher.PublishExecute(dsdData, plotConfig);

 

        Tx.Commit();

    }

 

    //reset the background plot value

    Application.SetSystemVariable("BACKGROUNDPLOT", bgPlot);

Here is a sample drawing to try the code :

Download Sample

Mirroring a DBText Entity

By Philippe Leefsma

Some time ago when this blog did not yet exist, I wrote the following .Net code to mirror a DBText entity in order to solve one of our ADN case. Many moons later that question popped up again, so here is the proposed solution. You will see that it isn’t so straightforward that you may think:

// Mirrors a DBText entity, by Philippe Leefsma 4/10/2013

 

[CommandMethod("MirrorTextCmd")]

public void MirrorTextCmd()

{

    Document doc = Application.DocumentManager.MdiActiveDocument;

    Database db = doc.Database;

    Editor ed = doc.Editor;

 

    //Entity selection

    PromptEntityOptions peo = new PromptEntityOptions(

        "\nSelect a text entity:");

 

    peo.SetRejectMessage("\nMust be text entity...");

    peo.AddAllowedClass(typeof(DBText), true);

 

    PromptEntityResult perText = ed.GetEntity(peo);

 

    if (perText.Status != PromptStatus.OK)

        return;

 

    peo = new PromptEntityOptions("\nSelect a mirror line:");

    peo.SetRejectMessage("\nMust be a line entity...");

    peo.AddAllowedClass(typeof(Line), true);

 

    PromptEntityResult perLine = ed.GetEntity(peo);

 

    if (perLine.Status != PromptStatus.OK)

        return;

 

    using (Transaction tr = db.TransactionManager.StartTransaction())

    {

        Line line = tr.GetObject(perLine.ObjectId, OpenMode.ForRead)

            as Line;

 

        Line3d mirrorLine = new Line3d(

            line.StartPoint,

            line.EndPoint);

 

        MirrorText(perText.ObjectId, mirrorLine);

 

        tr.Commit();

    }

}

 

void MirrorText(ObjectId TextId, Line3d mirrorLine)

{

    Database db = TextId.Database;

 

    using (Transaction tr = db.TransactionManager.StartTransaction())

    {

        BlockTableRecord btr = tr.GetObject(

            db.CurrentSpaceId,

            OpenMode.ForWrite) as BlockTableRecord;

 

        // Get text entity

        DBText dbText = tr.GetObject(TextId, OpenMode.ForRead)

            as DBText;

 

        // Clone original entity

        DBText mirroredTxt = dbText.Clone() as DBText;

 

        // Create a mirror matrix

        Matrix3d mirrorMatrix = Matrix3d.Mirroring(mirrorLine);

 

        // Do a geometric mirror on the cloned text

        mirroredTxt.TransformBy(mirrorMatrix);

 

        // Get text bounding box

        Point3d pt1, pt2, pt3, pt4;

        GetTextBoxCorners(

            dbText,

            out pt1,

            out pt2,

            out pt3,

            out pt4);

 

        // Get the perpendicular direction to the original text

        Vector3d rotDir =

            pt4.Subtract(pt1.GetAsVector()).GetAsVector();

 

        // Get the colinear direction to the original text

        Vector3d linDir =

            pt3.Subtract(pt1.GetAsVector()).GetAsVector();

 

        // Compute mirrored directions

        Vector3d mirRotDir = rotDir.TransformBy(mirrorMatrix);

        Vector3d mirLinDir = linDir.TransformBy(mirrorMatrix);

 

        //Check if we need to mirror in Y or in X

        if (Math.Abs(mirrorLine.Direction.Y) >

            Math.Abs(mirrorLine.Direction.X))

        {

            // Handle the case where text is mirrored twice

            // instead of doing "oMirroredTxt.IsMirroredInX = true"

            mirroredTxt.IsMirroredInX = !mirroredTxt.IsMirroredInX;

            mirroredTxt.Position = mirroredTxt.Position + mirLinDir;

        }

        else

        {

            mirroredTxt.IsMirroredInY = !mirroredTxt.IsMirroredInY;

            mirroredTxt.Position = mirroredTxt.Position + mirRotDir;

        }

 

        // Add mirrored text to database

        btr.AppendEntity(mirroredTxt);

        tr.AddNewlyCreatedDBObject(mirroredTxt, true);

 

        tr.Commit();

    }

}

 

// We need a bunch of P/Invoked functions to retrieve a DBtext

// bounding box because "acedTextBox" API is not exposed to .Net

 

public struct ads_name

{

    public IntPtr a;

    public IntPtr b;

};

 

// Exported function names valid only for R19

 

[DllImport("acdb19.dll",

    CallingConvention = CallingConvention.Cdecl,

    EntryPoint = "?acdbGetAdsName@@YA?AW4ErrorStatus@Acad@@AAY01JVAcDbObjectId@@@Z")]

public static extern int acdbGetAdsName32(

    ref ads_name name,

    ObjectId objId);

 

[DllImport("acdb19.dll",

    CallingConvention = CallingConvention.Cdecl,

    EntryPoint = "?acdbGetAdsName@@YA?AW4ErrorStatus@Acad@@AEAY01_JVAcDbObjectId@@@Z")]

public static extern int acdbGetAdsName64(

    ref ads_name name,

    ObjectId objId);

 

public static int acdbGetAdsName(ref ads_name name, ObjectId objId)

{

    if (Marshal.SizeOf(IntPtr.Zero) > 4)

        return acdbGetAdsName64(ref name, objId);

 

    return acdbGetAdsName32(ref name, objId);

}

 

[DllImport("accore.dll",

    CharSet = CharSet.Unicode,

    CallingConvention = CallingConvention.Cdecl,

    EntryPoint = "acdbEntGet")]

public static extern System.IntPtr acdbEntGet(

    ref ads_name ename);

 

[DllImport("accore.dll",

    CharSet = CharSet.Unicode,

    CallingConvention = CallingConvention.Cdecl,

    EntryPoint = "acedTextBox")]

public static extern System.IntPtr acedTextBox(

    IntPtr rb,

    double[] point1,

    double[] point2);

 

void GetTextBoxCorners(

    DBText dbText,

    out Point3d pt1,

    out Point3d pt2,

    out Point3d pt3,

    out Point3d pt4)

{

    ads_name name = new ads_name();

 

    int result = acdbGetAdsName(

        ref name,

        dbText.ObjectId);

 

    ResultBuffer rb = new ResultBuffer();

 

    Interop.AttachUnmanagedObject(

        rb,

        acdbEntGet(ref name), true);

 

    double[] point1 = new double[3];

    double[] point2 = new double[3];

 

    // Call imported arx function

    acedTextBox(rb.UnmanagedObject, point1, point2);

 

    pt1 = new Point3d(point1);

    pt2 = new Point3d(point2);

 

    // Create rotation matrix

    Matrix3d rotMat = Matrix3d.Rotation(

        dbText.Rotation,

        dbText.Normal,

        pt1);

 

    // The returned points from acedTextBox need

    // to be transformed as follow

    pt1 = pt1.TransformBy(rotMat).Add(dbText.Position.GetAsVector());

    pt2 = pt2.TransformBy(rotMat).Add(dbText.Position.GetAsVector());

 

    Vector3d rotDir = new Vector3d(

        -Math.Sin(dbText.Rotation),

        Math.Cos(dbText.Rotation), 0);

 

    Vector3d linDir = rotDir.CrossProduct(dbText.Normal);

 

    double actualWidth =

        Math.Abs((pt2.GetAsVector() - pt1.GetAsVector())

            .DotProduct(linDir));

 

    pt3 = pt1.Add(linDir * actualWidth);

    pt4 = pt2.Subtract(linDir * actualWidth);

}

Here is a screenshot of the astonishing result!