Sketch will not close as loop

[Anonymous]

Hey,

I cannot find a reason why my sketch isn't a "closed loop" which I could extrude. I have the "check sketch" add-in installed and it shows some points on lines that are crossing each other, but there doesn't seem to be any open loops.

The file is originally an export from BoardCAD "bezier as polyline DXF", which I opened in F360, checked the sketch and fixed the missing points and saved as a DXF to open in Illustrator (the original DXF that BoardCAD produced couldn't be opened in Illustrator... Weird.) I then made the notches, rounded rectangle-holes and an offset (the offsetting couldn't be done in F360 because there seemed to be too many nodes in the sketch and F360 would just get jammed) and then exported as DXF. Now I am in this situation where I have made a ton of similar sketches in Illustrator and only one out of ten is a closed loop. I would deeply appreciate help, thanks!

[etfrench · Accepted solution]

Your sketch has several lines that don't extend far enough to meet other lines.  The 'Divide and Conquer' method works fairly well for this type of error.

The most likely cause for the Offset command failure is the crossing lines.  Use the Trim command to clean these up and the offset command will work on the entire perimeter.

Another possible sketch problem is some CAD programs add a small Z axis attribute to geometry and Fusion 360 correctly interprets this as 3d geometry.  There is a context menu item, which only appears when the Z value is not 0, to fix this. (Your file doesn't have this error.)

[Anonymous]

Wow, thank you so much! The extend function was new for me as well as the "divide and conquer" method, which is a good tactic. 

About the offset: the file that I tried the offset on was one without the crossing lines; it was the file that came almost clean (minus one missing line) out of BoardCAD. It was taking way too long to choose the sketch and freezing up (I'm sometimes too impatient). I attached this original file if you are interested in taking a look. 

Thanks again. 🙂

[etfrench]

I didn't have any issues opening the dxf in Fusion 360.

[Maciej_Rogowski]

Hello,

There is a new add-in called Fill Gaps in Sketch on the Autodesk App Store. It fills gaps between end points of lines and curves in a sketch. It allows to create closed profiles without gaps. 

Here is a link to the Autodesk App Store:

https://apps.autodesk.com/FUSION/en/Detail/Index?id=1232847965088759508&appLang=en&os=Win64

and a link to an instructional video on YouTube:

https://www.youtube.com/watch?v=6-J9GFCsWzQ