AutoCADでVB.NETを使い自動で五角形を描かせることに成功！

一辺が100の五角形を描くVB.netプログラム。任意の中心を指定するだけ。

VBのソースコードの部分だけ以下のようにChatGPTに質問して書いてもらった。

Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.EditorInput
Imports Autodesk.AutoCAD.Geometry
Imports Autodesk.AutoCAD.Runtime

Public Class Class1

    <CommandMethod("PENTAGON")>
    Public Sub DrawPentagon()
        ' ダイアログを表示して中心点を取得
        Dim dialogResult As PromptPointResult = GetPoint("Specify center point: ")
        If dialogResult.Status <> PromptStatus.OK Then
            Exit Sub
        End If
        Dim centerPoint As Point3d = dialogResult.Value

        ' 一辺が100の五角形を描画
        DrawRegularPentagon(centerPoint, 100)
    End Sub

    Private Function GetPoint(message As String) As PromptPointResult
        Dim editor As Editor = Application.DocumentManager.MdiActiveDocument.Editor
        Dim promptOptions As PromptPointOptions = New PromptPointOptions(message)
        Dim pointResult As PromptPointResult = editor.GetPoint(promptOptions)
        Return pointResult
    End Function

    Private Sub DrawRegularPentagon(centerPoint As Point3d, sideLength As Double)
        Dim doc As Document = Application.DocumentManager.MdiActiveDocument
        Dim db As Database = doc.Database

        Using trans As Transaction = db.TransactionManager.StartTransaction()
            Try
                ' ブロックテーブルとブロックテーブルレコードを開く
                Dim bt As BlockTable = trans.GetObject(db.BlockTableId, OpenMode.ForRead)
                Dim btr As BlockTableRecord = CType(trans.GetObject(bt(BlockTableRecord.ModelSpace), OpenMode.ForWrite), BlockTableRecord)

                ' 一辺が100の五角形を作成
                Dim pentagonPoints As Point2dCollection = GetRegularPentagonPoints(centerPoint, sideLength)
                Dim poly As Polyline = New Polyline()
                For Each point As Point2d In pentagonPoints
                    poly.AddVertexAt(poly.NumberOfVertices, point, 0, 0, 0)
                Next

                poly.Closed = True
                btr.AppendEntity(poly)
                trans.AddNewlyCreatedDBObject(poly, True)

                trans.Commit()
            Catch ex As Exception
                Application.ShowAlertDialog("Error: " & ex.Message)
                trans.Abort()
            End Try
        End Using
    End Sub

    Private Function GetRegularPentagonPoints(centerPoint As Point3d, sideLength As Double) As Point2dCollection
        Dim points As Point2dCollection = New Point2dCollection()

        For i As Integer = 0 To 4
            Dim angle As Double = i * (2 * Math.PI) / 5
            Dim x As Double = centerPoint.X + sideLength * Math.Cos(angle)
            Dim y As Double = centerPoint.Y + sideLength * Math.Sin(angle)
            points.Add(New Point2d(x, y))
        Next

        Return points
    End Function

End Class

AutoCADでコマンド「PENTAGON」と入力し、中心を指定すると・・・

このように一瞬で一辺100の五角形が出現した。マウスでカチャカチャやったら何秒かかるだろうか？

小さなプログラムのブロックをたくさん作って組み合わせていけば、作図スピードが何十倍にも上がるのは言うまでもない。