I am trying to extend several 3D Polylines to where they intersect a single surface.
I haven't been able to figure out a quicker way of doing this than by drawing a construct 3D polyline between the top and toe of the slope I want to extend up to for each 3D Polyline I want to extend, then trimming where these two lines intersect...
Is there really no way to utilise the surface for extending / trimming 3D Polylines?
I am using a 64 bit machine with AutoCAD Civil 3D 2013 on Windows 7.
Any advice would be much appreciated
Solved! Go to Solution.
Solved by troma. Go to Solution.
neilyj (No connection with Autodesk other than using the products in the real world)
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Hi neilyj,
This isn't quite what I'm after.
The levels of the 3D polylines are set. I just want them trimmed to where they cross the surface plane.
neilyj (No connection with Autodesk other than using the products in the real world)
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You can create a feature line perpendicular to the 3Dpolys and grade to the surface horizontally. Will this work in your case?
Hmm, I don't think doing this will identify where the 3D Polyline would cross the surace?
Can you draw me a picture or post a drawing just so I can be sure I understand the issue. I might be able to do something with vlisp.
Hi tcorey.
I've attached a picture below.
In this case I am trying to extend the magenta 3D Polylines to the surface.
Sorry to get your hopes up. I took a look at it and it would take me too long to write the code.
If you joined the ends of your magenta lines with a feature line, graded this feature line horizontally to the surface, and then extend the magenta lines to the feature line created on the surface using the trim function (maybe exploding it to a polyline first) ?
neilyj (No connection with Autodesk other than using the products in the real world)
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Mark Green
Working on Civil 3D in Canada
Sorry, overlooked that there was a grade involved, haven't done this recently.
Over the last few years I have often wished there would be a function to intersect a line with a surface, it would be a great help for developing a design, just to see where a pipe or road CL was headed in relation to a surface. Ended up creating this little horizontal feature line at 90deg to the CL, and projecting (grading) it on to the surface. Attaching a road cross section to the end of the CL and grading that to the surface achieves the same thing.
After having a similar issue on a different project today, I did a quick google search and came across my old post here. Your solution effectively gets the point I need and is simple enough to do. Thanks.
I use the grading object method but sometimes I may also use the zero contour. Take the 3d polys and place them in a surf. Run a vol srf between the the two surfaceas and extract the zero contour. This is the trim line for the 3d polys.
Not much of a time savings but I sometimes want that zero contour for limit of grading or other boundary needs.
John Mayo
This challenge was presented in another recent thread. A couple of solutions were offered. One that you might find useful utilizies a daylight grading but in a different way. You can review the approach in my replies to the thread found here:
I'm not saying it is a better solution but it may be simpler in some ways.
I forgot to add a step. You will probablt need to use the lengthen command on the 3d polys befrore building the surface. Lengthen them any distance that extends them beyond the base/eg surface.
John Mayo