topic iLogic. Inventor 2020 Professional in Inventor Programming Forum

iLogic. Inventor 2020 Professional

john_combo — Sat, 07 Feb 2026 15:44:57 GMT

Hi everyone!

I’m using Inventor 2020 Pro. Right now I’m trying to write a script to automate part of my workflow.

In a folder I have several files that contain flat parts and follow a similar naming pattern.

In a loop I:

take each file,
open it,
get all faces of the flat part,
find the face with the largest area,
and try to export that selected face as a DXF.

I’m able to find the face with the maximum area in code, but after that I can’t get the export function to work with that face.

Here’s my code.

... Dim partFiles As String() = Directory.GetFiles(sourceFolder, "*.ipt", SearchOption.TopDirectoryOnly) ... Try Dim compDef As Inventor.PartComponentDefinition = partDoc.ComponentDefinition Dim maxFace As Inventor.Face = Nothing Dim maxArea As Double = -1.0 For Each body As Inventor.SurfaceBody In compDef.SurfaceBodies For Each face As Inventor.Face In body.Faces If face.SurfaceType = Inventor.SurfaceTypeEnum.kPlaneSurface Then Dim evaluator As Inventor.SurfaceEvaluator = face.Evaluator Dim area As Double = evaluator.Area If area > maxArea Then maxArea = area maxFace = face End If End If Next Next If maxFace Is Nothing Then Return "[Skip] " & System.IO.Path.GetFileName(partPath) & " — no flat faces found" End If Dim selectSet As Inventor.SelectSet = partDoc.SelectSet selectSet.Clear() selectSet.Select(maxFace) Dim dxfPath As String = System.IO.Path.Combine(dxfFolder, System.IO.Path.GetFileNameWithoutExtension(partPath) & ".dxf") Dim exportStatus As String = ExportSelectedFaceViaUI(dxfPath) Return "[OK] " & System.IO.Path.GetFileName(partPath) & " → " & exportStatus Finally If Not isAlreadyOpen AndAlso partDoc IsNot Nothing Then partDoc.Close(False) ElseIf partDoc IsNot Nothing Then partDoc.Activate() End If End Try

Maybe someone more experienced can take a look and point out what I’m doing wrong. I realize it might look like total nonsense, but I really need some guidance.

I can’t get the face export to DXF working — the files just never show up in the target folder. I double-checked that the script returns the correct area for the largest face, so it is finding that face and selecting it. (From what I’ve read, programmatically selecting a face doesn’t necessarily produce any visible selection highlight in the UI.)

My guess is that in the Inventor 2020 Pro API there may not be a way to export a selected face directly.

Thanks for taking the time to read my question.

Re: iLogic. Inventor 2020 Professional

john_combo — Sat, 07 Feb 2026 15:55:43 GMT

I can do this manually without any issues. But I seriously doubt I can keep doing it when I’ve got 200 files.

Re: iLogic. Inventor 2020 Professional

john_combo — Sat, 07 Feb 2026 16:14:03 GMT

Right now I’m trying a different approach: I select the face with the largest area, create a sketch on it by projecting the geometry, and then I try to export that sketch as a DXF. I’ll share the results a bit later.

Re: iLogic. Inventor 2020 Professional

kacper.suchomski — Sat, 07 Feb 2026 16:21:04 GMT

Are these files sheet metal parts?

Re: iLogic. Inventor 2020 Professional

john_combo — Sat, 07 Feb 2026 17:12:25 GMT

No — it’s just a regular flat part. It’s not sheet metal.

Re: iLogic. Inventor 2020 Professional

jnowel — Sat, 07 Feb 2026 17:25:03 GMT

check this relevant post: Solved: Export Face As DXF - Autodesk Community

Re: iLogic. Inventor 2020 Professional

john_combo — Sun, 08 Feb 2026 09:20:57 GMT

Thanks for your reply — I’ll take a short break to verify the info and then I’ll come back here with an update.

Re: iLogic. Inventor 2020 Professional

john_combo — Sun, 08 Feb 2026 20:14:49 GMT

Thanks — your answer really helped me! I was able to figure it out and fix the mistakes in my code. Now I’m getting the result I expected — awesome!

' Selecting the largest face Dim selectSet As Inventor.SelectSet = partDoc.SelectSet selectSet.Clear() selectSet.Select(maxFace) ' Export via the GeomToDXFCommand Dim dxfPath As String = System.IO.Path.Combine(dxfFolder, System.IO.Path.GetFileNameWithoutExtension(partPath) & ".dxf") Dim exportStatus As String = ExportFaceViaGeomToDXF(dxfPath, dxfFolder) ' New export function Private Function ExportFaceViaGeomToDXF(dxfPath As String, dxfFolder As String) As String Dim cmdMgr As Inventor.CommandManager = ThisApplication.CommandManager Dim exportDef As Inventor.ControlDefinition = Nothing Try exportDef = cmdMgr.ControlDefinitions.Item("GeomToDXFCommand") Catch ex As System.Exception Dim listPath As String = System.IO.Path.Combine(dxfFolder, "_command_names.txt") WriteControlDefinitionsList(listPath) Return "GeomToDXFCommand not found, commands: " & listPath End Try Try cmdMgr.PostPrivateEvent(Inventor.PrivateEventTypeEnum.kFileNameEvent, dxfPath) exportDef.Execute() Catch ex As System.Exception Return "Error of GeomToDXFCommand: " & ex.Message End Try Return "GeomToDXFCommand started (file: " & dxfPath & ")" End Function