topic Re: Interpolation of contour lines in AutoCAD Forum

Interpolation of contour lines

Anonymous — Mon, 22 Aug 2016 08:09:26 GMT

Hello,

i draw contour lines over a big area of planing. i draw them every 1 meter and gave them an elevation in their properties. now i want to draw lines every 20 cm. can i do that automaticly with some kind of interpolation command?

Re: Interpolation of contour lines

imadHabash — Mon, 22 Aug 2016 09:59:49 GMT

Hi and welcome to AutoDesk Forum,

i doubt that you can get such service directly from autocad. maybe with outsource help routines or another software.

Re: Interpolation of contour lines

Kent1Cooper — Mon, 22 Aug 2016 14:02:37 GMT

Welcome to these Forums!

That could probably be done with an AutoLisp routine. In fact, there may be something around these Forums about that already -- here's something closely related, and this is even closer though it only steers you in a direction, without providing a fleshed-out solution [I'll let you do more Searching]. But there are important questions:

What are the contour lines? LWPolylines? 3D Polylines? Splines? Something else like a Civil3D specialty object of some kind?

Are they always parallel to the World Coordinate System plane?

If they're Polylines, would adjacent contour lines always have the same number of vertices [or if Splines, the same number of fit points], and would the interpolation be straight between vertices [/fit points]? That doesn't seem likely, but see my input in the second link above for more about that -- subdividing equally along the overall length, rather than interpolating between vertices themselves, etc.

Re: Interpolation of contour lines

Kent1Cooper — Tue, 23 Aug 2016 13:31:44 GMT

@Kent1Cooper wrote:

.... there may be something around these Forums about that already -- here's something closely related, and this is even closer ....

And here is another I just ran across, that makes an average between two path objects. I haven't tried it or investigated its code, but I imagine it could be altered to run multiple times, finding vertex or fit-point locations at 0.2 x the distance between locations on the path objects, then 0.4 x, etc., to fill in all your intervals.

Re: Interpolation of contour lines

ahmed.abdelmotey — Tue, 30 Aug 2016 08:53:24 GMT

This is already available in AutoCAD Civil 3d but if you don't have it guess there are a lot of routines out there that could help you