Hatch all visible entities

[suisse_power]

Hi,

I'd like to automatically hatch all visible polygons of a drawing.

My vision of how to solve this is basically:

- for each visible drawing do

- pick internal point 

- hatch

- end for

I'm having trouble by automatically picking an internal point inside the polygon.

I've found these two methods : Crossing numbers and winding numbers (http://geomalgorithms.com/a03-_inclusion.html) but they don't seem to work if there are some polylines inside an polygon. ( example a but like polygon lol I know ... I'm inspired today hahaa )

Is there another solution to my problem for automatically picking an internal point inside a polygon ? Can I automatically hatch an polygon without picking it's internal point ?

Thank you in advance for your help.

[_gile]

Spoiler

Can I automatically hatch an polygon without picking it's internal point ?

For sure ! Look at the Hatch.AppendLoop(HatchLoopTypes, loopType, ObjectIdCollection ids) method:

[Hallex]

I aready have similar solution,

change hatch apttern and scale on whatever you need:

        <CommandMethod("mhat", CommandFlags.Modal Or CommandFlags.Session)> _
        Public Sub CreateHatchMulty()
            Dim doc As Document = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument
            Dim db As Database = doc.Database
            Dim ed As Editor = doc.Editor
            Try
                doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument
                Using docloc As DocumentLock = doc.LockDocument
                    Using tr As Transaction = doc.Database.TransactionManager.StartTransaction

                        'get active space 
                        Dim btr As BlockTableRecord = CType(tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite), BlockTableRecord)

                        Dim pso As PromptSelectionOptions = New PromptSelectionOptions
                        pso.MessageForRemoval = vbLf + "Must be selected closed contours!"
                        pso.MessageForAdding = vbLf + "Select contours: "
                        pso.SingleOnly = False
                        pso.SinglePickInSpace = False
                        pso.PrepareOptionalDetails = True
                        Dim filter As SelectionFilter = New SelectionFilter(New TypedValue() _
                             {New TypedValue(-4, "<or"), New TypedValue(-4, "<and"), New TypedValue(0, "lwpolyline"), New TypedValue(70, 1), _
                              New TypedValue(-4, "and>"), New TypedValue(0, "circle,,ellipse"), New TypedValue(-4, "or>")})
                        Dim res As PromptSelectionResult = ed.GetSelection(pso, filter)
                        If res.Status <> PromptStatus.OK Then Return
                        Dim sset As SelectionSet = res.Value

                        If sset.Count = 0 Then Return
                        Dim ent As Entity

                        For Each sobj As SelectedObject In sset
                            ent = TryCast(tr.GetObject(sobj.ObjectId, OpenMode.ForRead), Entity)

                            If ent Is Nothing Then Return

                            Dim hat As New Hatch()

                            ' add hatch first
                            btr.AppendEntity(hat)
                            tr.AddNewlyCreatedDBObject(hat, True)

                            hat.PatternAngle = 0.0
                            hat.PatternScale = 2.0
                            hat.Associative = True
                            hat.SetHatchPattern(HatchPatternType.PreDefined, "ANSI32")
                            ' append loop to hatch 
                            Dim dbObjIds As New ObjectIdCollection()
                            dbObjIds.Add(sobj.ObjectId)
                            hat.AppendLoop(HatchLoopTypes.External, dbObjIds)
                            hat.Layer = ent.Layer
                            hat.ColorIndex = 256
                            'bylayer,  may use as per entity colorindex
                            hat.HatchStyle = HatchStyle.Normal
                            hat.EvaluateHatch(True)

                        Next
                        tr.Commit()      'commit the transaction so the changes get written to db
                    End Using
                End Using
                doc.Editor.Regen()
            Catch ex As Autodesk.AutoCAD.Runtime.Exception
            Finally
                MsgBox("Pokey?")
            End Try
        End Sub

[suisse_power]

Thanks for your answers and the code however I always get "pokey?" meaning that it has ran into an exception, right ?

[Hallex]

Remove this message from Finally... End Try code block,

it's just for display when the end is riched

But how it works for you?

[suisse_power]

Hi Hallex,

Sorry for my late answer, I was dealing with personnal problems.

When I execute your code it asks me to select a contour, which I do over rectangles and circles.

I reclick to specify opposite corner.

The console says : "3 found" meaning that the 3 rectangles are found but not the circles.

Then I press enter and ... nothing happens ... besides the 'pokey message'.

Do you have an idea on what is the problem ?

I'm sorry I cannot correct your code since I'm not a very good programmer but I'm learning.