Break up drawing results in too many parts

I remember talking about this before, but i cant find what was said. When parts with etched bend lines are broken up from a manually nested drawing, the etch lines are getting turned into parts themselves. I assume this is because the end points of the lines are on the perimeter of the parts.

Is there anything that can be done to remedy this issue?? My sheet metal software generates the bend lines and puts them coincident with the edge of the part. That cannot be changed. I have to manually open each dxf in AutoCAD, move all the bend lines, Nest the parts, set the operations in sheetcam, then break up the drawing. It is really becoming a massive PITA and i am really hoping there is anything at all that can be done.

Sorry, I missed this post. Allowing for coincident lines is problematic. Due to the way computers handle numbers it is difficult to detect things like this.
Could you break up the nest in cad? It may be quicker to save the nest as a bunch of independent drawings.

I assume youre talking about roundoff errors. That does tend to bite in the butt a lot of times. But shouldn’t any line or point that close to another line or point be considered coincident anyways? Typical machines have tolerances down to 0.0001" at best and a computer passes that by far.

I’m sure there are some, but i cannot think of any typical cases where a line that close would not be part of that part anyways. No reasonable nest would have parts that close together. Unless it was nested for common line cutting, which i dont think sheetcam can do anyways. I would love to use common line cutting, but the toolpath of those nests just blows my mind.

Detecting inside is relatively easy. Detecting coincident or ‘close enough’ is hard. About the only way I could do it is to do an outside offset of the shape then check for inside that. It all starts getting very messy and complicated.

I would love to use common line cutting, but the toolpath of those nests just blows my mind.

Yup, that’s why I don’t support it. Common line cutting only works if it is generated from automatic nesting and it only works well for rectangular parts.

I guess i dont understand how it is actually doing the checks. I would think if you are able to detect inside, you could just as easily detect coincident. Things dont usually work how i think when it comes to programming though. I cant even begin to think of a way to offset a shape, i can see how that would get messy quickly.

Either way, it gets messy and time consuming editing dxfs manually and moving lines to make sure they are all inside the part just a little. Perhaps one day, enough people will ask for it to be worth your time to investigate further.

Just had an epiphany on this one Les… You know how the open contours on manually nested parts have been really giving me trouble. Less so since I have been nesting through the plugin, but still an issue sometimes… I’m not sure how the drawing importer works at all, but if it does or can recognize blocks, could an option be added to the drawing import options dialog “Use blocks for parts” so that parts could be saved as blocks in a DXF and the importer create parts based on the blocks in the DXF? That would solve the entire problem and no, or likely extremely rarely, need for break up manually nested drawing and having a crap-ton of parts that are single open lines! Voila!