topic Re: Find nearest polyline with block in .NET Forum

Find nearest polyline with block

wouter — Wed, 07 Nov 2012 16:24:19 GMT

Hi,

I'm using VB.NET to write a routine that autmatically calculates the area of the polyline nearest to a block (the pline surrounds the block) an then adds the area to the blocks attribute.

I managed to write the program to do this manually for a selected pline and block.

How can I automatically select a pline nearest to the selected blocks' insertion point?

Help is much appreciated..

thanks in advance!

Re: Find nearest polyline with block

Hallex — Wed, 07 Nov 2012 17:56:40 GMT

You might be want instead to select block within the crossingpolygon method,

if you've added just one block within, see if this helps:

        <CommandMethod("TUR")> _
        Public Shared Sub testUpdateRooms()
            Dim blockname As String = "ROOM"
            ' chnage block name
            Dim tagname As String = "ROOMAREA"
            ' change tag
            Dim db As Database = HostApplicationServices.WorkingDatabase
            Dim doc As Document = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument
            Dim ed As Editor = doc.Editor

            Dim filtpline As TypedValue() = New TypedValue(1) {New TypedValue(0, "lwpolyline"), New TypedValue(70, 1)}
            Dim pres As PromptSelectionResult = ed.SelectAll(New SelectionFilter(filtpline))
            If pres.Status <> PromptStatus.OK Then
                Return
            End If
            Dim filtblock As TypedValue() = New TypedValue(1) {New TypedValue(0, "insert"), New TypedValue(2, blockname)}
            Using tr As Transaction = doc.TransactionManager.StartTransaction()
                For Each sobj As SelectedObject In pres.Value
                    Dim ent As DBObject = tr.GetObject(sobj.ObjectId, OpenMode.ForRead, False)
                    Dim pline As Polyline = TryCast(ent, Polyline)
                    If pline Is Nothing Then
                        Return
                    End If
                    Dim pts As New Point3dCollection()
                    For n As Integer = 0 To pline.NumberOfVertices - 2
                        pts.Add(pline.GetPoint3dAt(n))
                    Next
                    Dim res As PromptSelectionResult = ed.SelectCrossingPolygon(pts, New SelectionFilter(filtblock))

                    If res.Status <> PromptStatus.OK Then
                        Continue For
                    End If

                    Dim sset As SelectionSet = res.Value
                    If sset.Count = 0 Then
                        Continue For
                    End If
                    ' if more than one block found, then make polyline to be cyan colored to select room with extrafluous blocks
                    If sset.Count > 1 Then
                        pline.UpgradeOpen()
                        pline.ColorIndex = 121
                    Else
                        Dim ids As ObjectId() = sset.GetObjectIds()
                        Dim blkobj As DBObject = tr.GetObject(ids(0), OpenMode.ForRead, False)
                        Dim bref As BlockReference = TryCast(blkobj, BlockReference)
                        If bref Is Nothing Then
                            Continue For
                        End If
                        Dim atts As AttributeCollection = bref.AttributeCollection
                        For Each id As ObjectId In atts
                            Dim attref As AttributeReference = DirectCast(tr.GetObject(id, OpenMode.ForRead, False), AttributeReference)
                            If attref.Tag = tagname Then
                                bref.UpgradeOpen()
                                attref.UpgradeOpen()
                                attref.TextString = Math.Round(pline.Area, 2).ToString() '' i.e. precision 2 decimals, or
                                ' possible to use a field with pline area as well
                                attref.DowngradeOpen()
                                bref.DowngradeOpen()
                            End If
                        Next
                    End If
                Next
                tr.Commit()
            End Using
        End Sub

Re: Find nearest polyline with block

wouter — Thu, 08 Nov 2012 08:07:02 GMT

Tnx, I'm going to try it!

Re: Find nearest polyline with block

wouter — Thu, 08 Nov 2012 10:58:44 GMT

It is a nice solution but it worked partly.

First, I changed SelectCrossingPolygon to SelectWindowPolygon because some blocks are bigger dan the room, so they overlap with another room.

Secondly Some plines contain arcs, so the the returned vertices not always create a polygone that is around the block.

Is there a way to also use of arcs in the pointselection to form the SelectWindowPolygon?

Re: Find nearest polyline with block

Hallex — Thu, 08 Nov 2012 14:04:44 GMT

I think in this case you an to gather the points along the polyline route

with small steps between,then gather them all in the point3dcollection

to perform the window selection

Re: Find nearest polyline with block

wouter — Fri, 23 Nov 2012 16:33:56 GMT

tnx for your help!

Do you think it's possible to make a selection for just the insertion point of the block?

The size of the attributes changes with the different text lengths.
That makes it difficult to select just one block, because the text overlaps more then one pline...

Thanks,

Wouter