Need Advice on Importing AutoCAD DWG files into Inventor

[Bill Tillman]

Ok, my associates and I have been handed a new project. The clients have provided us with AutoCAD dwg files of their extrusion die profiles. They want us to build a model of their custom storefront system in Inventor. I have used Inventor for sheet metal and even that was a year ago. So I'm a little rusty on the process again.

As I understand the docs, one should be able to import the autocad drawings which are closed polylines to show the profiles of aluminum extrusions. But when I do this the process is far from flawless. This job is all in metric so I open up a Standard (mm) .ipt file. I have tried several methods, first being to copy to object from AutoCAD into the clipboard and then paste it into the Inventor sketch. But I end up with the shape way out of reach from the origin and my attempts to move the shape are not working so well. Another approach I have tried is to import the autocad dwg file directly. Both options have worked and I've been able to extrude the shape. I think from there I can add the notches and holes similarly to the way I did with the sheet metal layouts last year. And should I be importing them as closed polylines or just lines and let Inventor work that out? I seem to have found a way by trial and error that Inventor will do this with just lines and allowed the shape to be extruded to a given length.

Now the next question becomes, I want to assemble these parts into a frame, with basically four sides. I am thinking that the frame (whatever) of Inventor will be the tool for this but I haven't gotten that far yet. So would it be better to simple make several of the parts, with the machining taken care of and then put these parts into an assembly file.

Also, I was told that I could basically put the two extrusions at the 90° angle to one another and Inventor would figure out what machining would need to be done to mate the two parts together, notching, etc...

Maybe I'm overreaching here and possibly have been misinformed about a software's capability (again). Any pointers on the use of Inventor with extrusions particularly with curtain wall would be appreciated.

BTW - My searches have found several videos on youtube about using Inventor with curtain wall but these were just mainly presentation animations showing field installation with very loud and annoying music playing. Very innovative but nothing like what I'm looking for to get started.

[Bill Tillman]

Some more trial and error shows that if I save the AutoCAD dwg file with the profile saved as a region, which allows me to run MASSPROP and find the Centroid. I then move the profile so the centroid ends up at 0,0. Save the file and then import it into Inventor 2012. The part ends up right where I want it with the centroid being on the origin. Now to extrude it and apply some machining to see how the rest of this works.

J.D. will kill me because I haven't yet figured out how to make the constraints using this method. But who has time for details, we just need to get toner on paper as quickly as possible. Damn the torpedoes and full speed ahead.

[JD Mather]

... in addition to information in your other post, not having seen your profiles but assuming they are somewhat complex - I would investigate using Sketch Blocks in Inventor.
You can bring in your AutoCAD profiles into Inventor sketches (assuming they are actually correct) and not worry about constraints (for now) when you convert to an Inventor Sketch Block you can then constrain/rotate/whatever the Block without worring too much about the geometry inside the block. Again, this assumes that geometry is correct.

I assume you have read this
http://home.pct.edu/~jmather/SkillsUSA%20University.pdf

[Bill Tillman]

JD, yes I read that document at your recommendation last summer when I first started with Inventor and again over this past weekend. It allowed me at least turn off the grid which kind of get in the way in this work. I have a copy of Mastering Inventor 2011 which I'm also sure will be useful as well as view the on-line tutorials from the AutoDesk website.

The extrusions I'm working with are rather complex but nothing to be intimidated by. Unfortunately due to a NDA I had to sign, I cannot post any of the shapes. If the time comes and it's necessary I can post something that is similar. Here is basically what I found thus far.

By turning the lines in the profiles in AutoCAD to closed polylines and then turning these into regions I can import them into Inventor and get them located like I want. If I try to apply a dimension to anything Inventor will report that by doing so it will "over constrain" the sketch. I applied a few dimensions just to check that all is well, and so far it is. I am trusting the client's drawings although I've had to make a few revisions where duplicate lines were involved in their work. I am able to extrude the shape and I have just started making sketches to apply the machining needed for the parts. It's slow going but I'm making progress. I learned a lot about Inventor last year but that was for sheet metal work. Many of the same principals apply for these extruded parts. I'm anxious to get enough of them made that I can actually assembly one of the frames. Hope to be doing that by tomorrow.

[JD Mather]

JD

By turning the lines in the profiles in AutoCAD to closed polylines and then turning these into regions I can import them into Inventor and get them located like I want. If I try to apply a dimension to anything Inventor will report that by doing so it will "over constrain" the sketch. .

Not sure why you are getting this - I will have to do an experiment with regions myself, but look in to Sketch Blocks. Right click on the sketch and select Edit and the click the Sketch Block icon. Select the geometry, specify the base point for insertion and give it a name and save. Now you can move it around as a block. I assume you want the COG at the origin.