How to Save Inv drawings to acad format with polylines

[stevec781]

I have a drawing in Inventor 2010 of nested parts for cnc cutting and I want to save it to dwg or dxf and have the closed profiles come across as polylines. So far I have only been able to get lines arcs and splines. Is there a way to get inventor to recognise a closed loop in a drawing view and export it using polylines?

[scottmoyse]

Not that i have ever been able to find. However, one blessing is that as long as the lines in inventor do create a closed loop then once in acad, its an easy pedit command with non, if not very little, 'cleaning' of the geometries required. What CAM software are you using?

[stevec781]

We send to various external cutters and they prefer closed polylines. We nest by hand so to manually pedit all the parts after nesting in Inventor is going to be painfull as the parts are tighly nested and have lots of line segments. We used to do all this only in acad but were hoping Inventor would speed things up - which it would have if it could generate polylines - if not it will probably be better to stay in the 2D world for this one.

We either need to be able to export as polyline from Inventor or have acad pedit command have a select loop option - but I cant find either 😞

Autodesk developers please consider this one

[scottmoyse]

pedit
m for multiple
select the entire drawing
j for join
0.1 fuzz distance

The whole lot, done, in a matter of seconds.

You may want to flatten and then go
express>modify>delete duplicate objects with all of the options turned on
do this layer by layer (if you use layers for the cut files) by turning them on and off.

[scottmoyse]

and its select loop kind the same thing as boundary? but pedit multiple is way better any way

[scottmoyse]

oh and as a matter of interest what process do you use for nesting manually in inventor? do you do it in assemblies using sketches (representing the material), and constraining the parts with the sketches?

[scottmoyse]

I have just noticed, that if you right click on a sketch in a part. then select export face as, and save as a dwg, then some of the geometries come through as 2D polylines. Not all of them did but i assume that is because, although i have sucessfully extruded from the sketch, they aren't true closed loops... Its could be worth you investigating.

[stevec781]

Thanks I never knew pedit using multiple would join seperate objects at the same time.

I am still testing the best workflow but planning to nest by creating a part for the sheet, then in an assembly mate each part to be cut with a face/face mate to the plate part and then position them. Then create drawing view of assembly at 1:1 scale and export as dxf.

In acad I just used groups so that I could move the part, its labels and mark lines at the same time. Is quite fast once you get going. But hoping inventor will give the advantage of being able to make changes to the parts without having to then replace them in the nest.

[scottmoyse]

yup a few golden commands in acad for cut file creation:

Flatten
Overkill by layer (delete duplicates)
Pedit (multiple)
then a corker

tools>quick select>polylines>closed>equals False

highlights all of the open polylines so you can fix them and close them.

I use alphacam for nesting and programming and have quite a drawn out process to gets parts from inventor to the CNC via acad and alphacam (due to part number requirements etc..). trying to learn VB.net to rectify that.

So out of interest what CAM software are you using?

[stevec781]

Thanks. Been using acad for years and didnt know about some of them.

I dont know about VB.net but I learnt VBA from a book by Joe Sutphin called Autocad 2000 VBA (yep its been a while) and found it easy to write macros. All of my cut length calcs, wastage, checking for open poly lines, auto closing open polylines, layer checking, checking for small line segments etc is done by VBA macro.

I dont have any CAM software. I just send the files to the material suppliers who cut for me. One uses Sigma nest, the other I have no idea. They both just want a clean dxf from me which is why its all manual nesting for me.

Thanks for your help.