Making a COM Connection to AutoCAD using VB.NET
Inter-process communication allows you to create dynamic workflows between software applications. This can be achieved in a variety of ways (COM, Remoting…)
The example below provides some basic code for establishing a COM connection to AutoCAD using VB.NET. After a connection is established, it is then possible to send remote commands to the AutoCAD command-line as well as automate other features in the program.

SEND A COMMAND
Imports System
Imports System.Runtime.InteropServices
Imports Autodesk.AutoCAD.Interop
'the correct progID for AutoCAD 2010 is "AutoCAD.Application.18"
Dim progID As String = "AutoCAD.Application.18"
Dim acApp As AcadApplication
acApp = Marshal.GetActiveObject(progID)
acApp.Visible = True
' you can now send commands to the the AutoCAD command-line
acApp.ActiveDocument.SendCommand()