Plines are not breaking at intersection with another object

[Anonymous]

Hello, 

I am working with some contour lines sent to us from one of our clients, and I have been successfully breaking them to rectangles that I made to use as borders to create smaller maps. I have been using a lisp (BreakObjects23.LSP) and using the command BreakTouching successfully, but I have come across some contour lines that will not break to the rectangle. I have also tried just breaking them one at a time using the break command and the object snap set to the intersection, and that will not work either. I can only think that something is wrong with the contour lines, but I cannot figure out what it is.

[john.uhden · Accepted solution]

You will have to post a sample drawing containing your uncooperative contours, but my first guess is that they are at a different elevation (as contours usually are) from the "box" you want to use as the breaking boundary.  Have you tried the TRIM command instead?  It doesn't seem to mind any differences in elevation.

Of course you are reminding me of my early experiences with AutoCAD 2.7 on a 286.  It took so long to trim one contour that I fell asleep at my desk.  At least when I woke up the contour was trimmed.

[Anonymous]

Thank you, yes the elevations were different. The funny thing is that some of the contour lines were at 0, and those contour lines were already breaking just fine. Since the clients included the elevation in the attributes/object data, I'm going to set the geometry elevation to 0 so that I can break them since it should be faster.