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    by Clint Brown

    I get asked a lot of questions about Inventor drawings an AutoCAD, and the Inventor DWG file format. There seems to be a lot of mis-information and confusion around, so I would like to debunk the myths, and separate some facts from fiction.

    Consideration 1 – IDW v DWG: 

    Why do people use IDW’s:

    1)      They always have, and have never thought of moving to DWG

    2)      There is concern over Confusion between AutoCAD and Inventor DWG’s (see point 6 below)

    3)      IDW’s can be smaller. Because DWG files have additional functionality built in, they are sometimes slightly bigger in file size.



    But there is Absolutely no need to use IDW files any more. The additional  functionality of the Inventor DWG makes it much more versatile. The IDW format was the original Inventor drawing format, way back in the early days when Inventor was unable to create DWG’s. The IDW format is maintained by Autodesk for this reason.


    Moving over to DWG’s is logical and easy, for several reasons: 

    1)      Inventor DWG’s can be opened by Native AutoCAD, this means you can collaborate very easily

    2)      Inventor DWG’s are partly read only in AutoCAD, you can’t change the geometry, but you can add dimensions and you can draw on top of the geometry displayed

    3)      The Inventor DWG format has additional functionality, like the ability to insert DWG blocks amongst other things.

    4)      You can quickly convert all of your IDW’s to Inventor DWG format by doing a file “save as”

    5)      You can use the Inventor Task Scheduler to batch convert your IDW files to DWG’s, for help with this,

    see:Migrate files using Task Scheduler

    6)      The AutoCAD DWG Launcher understands the difference between an AutoCAD DWG and an Inventor DWG, so you don’t

    have to worry about using the wrong application when double clicking on a random DWG file. If you do have any issues,

    you can quickly set the record straight, by right clicking on the file, choosing “Open with” and setting AutoCAD DWG Launcher as the default program.



    Consideration 2 – Inventor DWG’s in AutoCAD:

    An Inventor DWG file can be opened very easily in AutoCAD, as well as in DWG TrueView. This means that you can share your drawing with someone who does not have Inventor. This alone will open up collaboration opportunities within your organisation and supply chain

    So what does an Inventor DWG look like in AutoCAD?

    Very similar to the image below, in this instance we have opened the drawing in DWG TrueView (a free AutoCAD file viewer). In AutoCAD you can see the views created in Inventor, but you cannot modify the drawing view, this is a good thing! The reason I say that, is that we still have a link to the 3D model, so any changes we make to the model will update in the Inventor DWG file (these changes will be reflected in AutoCAD). You are able to draw on top of the views, to add more detail for instance, and you are able to annotate the drawing in AutoCAD.


    What if I want to Edit the geometry?

    Well to do this, you would need to either edit the 3D model, or break the link to the 3D model and save out an AutoCAD DWG file. Saving out an AutoCAD DWG will strip the drawing of any real intelligence, and basically give you lines, circles and arcs of the drawing (keep reading for more options)

    One of the major drawbacks of this, is that the layering that an AutoCAD user would expect is different, as Inventor treats layers slightly differently.

    Border, Dimension, Hatch, Symbol, Hidden, 0 & Defpoints should all be pretty much self-explanatory, but the difference is, that each individual component will not be on it’s own layer, Inventor does not create parts on layers, as it uses an intelligent 3D model to generate the drawing views, so the other layers you see are Visible (these are the outer lines of the model, hard model edges), Visible Narrow (tangent edges and soft model edges).



    Inventor DWG’s are brilliant, they allow you to easily collaborate across multiple platforms, the image below is my Inventor drawing opened up in AutoCAD WS (think cloud, mobile…). Let me know what you think, and give DWG’s a try if are not already using them.