Insert block and matrix transform it to p1 and p2 possition problem...

[jokiller70]

I want to insert a block and rotate it to 2 points that i select in modelspace. But i get eCannotScaleNonUniformly with this code;

                        Dim acPt3d As Point3d = New Point3d(0, 0, 0)
                        Dim acVec3d As Vector3d = acPt3d.GetVectorTo(p1)
                        blockRef.TransformBy(Matrix3d.Displacement(acVec3d))
                        Dim zAxis As Vector3d = curUCS.Zaxis
                        Dim xAxis As Vector3d = p1.GetVectorTo(p2).GetNormal
                        Dim yAxis As Vector3d
                        If xAxis.IsEqualTo(zAxis) Then
                            yAxis = curUCS.Yaxis
                            zAxis = xAxis.CrossProduct(yAxis).GetNormal
                        Else
                            yAxis = zAxis.CrossProduct(xAxis).GetNormal
                        End If
                        blockRef.TransformBy(New Matrix3d(New Double() {xAxis.X, yAxis.X, zAxis.X, p1.X, xAxis.Y, yAxis.Y, zAxis.Y, p1.Y, xAxis.Z, yAxis.Z, zAxis.Z, p1.Z, 0, 0, 0, 1}))
 

[Matti72]

Your Matrix probably contains a scale factor (not all Vectors seems to be normals)...

Here should be a solution for your problem.

http://adndevblog.typepad.com/autocad/2012/08/remove-scaling-from-transformation-matrix.html

[jokiller70]

Still same problem...

Dim mx As Matrix3d = New Matrix3d(New Double() {xAxis.X, yAxis.X, zAxis.X, p1.X, xAxis.Y, yAxis.Y, zAxis.Y, p1.Y, xAxis.Z, yAxis.Z, zAxis.Z, p1.Z, 0, 0, 0, 1})
                        Dim axes As New List(Of Vector3d)

                        For i As Integer = 0 To 2
                            Dim vec As New Vector3d(mx(i, 0), mx(i, 1), mx(i, 2))
                            vec = vec.GetNormal()
                            axes.Add(vec)
                        Next

                        Dim mx2 As Matrix3d = New Matrix3d(New Double() _
                        {
                          axes(0).X, axes(0).Y, axes(0).Z, mx(0, 3),
                          axes(1).X, axes(1).Y, axes(1).Z, mx(1, 3),
                          axes(2).X, axes(2).Y, axes(2).Z, mx(2, 3),
                          mx(3, 0), mx(3, 1), mx(3, 2), mx(3, 3)
                        })

                        blockRef.TransformBy(mx2)

[augusto.goncalves]

from your initial description and this last code, I'm not sure what you want to achieve here...

can you try add an image to this thread showing what you want?

[jokiller70]

I want to insert a block(almost only a straight line) at p1 and rotate/transform it so it points to p2.

In VB I set a new ucs between the points and inserted the block.

[_gile]

Hi,

IMO, the most easier way is to define your block as a line along Z axis (e.g. from 0,0,0 to 0,0,1) and then, just use a plane which origin is the base point and the normal the vector from the base point to the second one to transform the block.

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

            var options = new PromptPointOptions("\nBase point: ");
            var result = ed.GetPoint(options);
            if (result.Status != PromptStatus.OK)
                return;
            var basePt = result.Value;

            options.Message = "\nDirection point: ";
            options.BasePoint = basePt;
            options.UseBasePoint = true;
            result = ed.GetPoint(options);
            if (result.Status != PromptStatus.OK)
                return;
            var dirPt = result.Value;

            var ucs = ed.CurrentUserCoordinateSystem;
            basePt = basePt.TransformBy(ucs);
            dirPt = dirPt.TransformBy(ucs);

            using (Transaction tr = db.TransactionManager.StartTransaction())
            {
                var bt = (BlockTable)tr.GetObject(db.BlockTableId, OpenMode.ForRead);
                var curSpace = (BlockTableRecord)tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite); 

                var plane = new Plane(basePt, basePt.GetVectorTo(dirPt));

                var br = new BlockReference(Point3d.Origin, bt["test"]);
                br.TransformBy(Matrix3d.PlaneToWorld(plane));
                curSpace.AppendEntity(br);
                tr.AddNewlyCreatedDBObject(br, true);
                tr.Commit();
            }
        }