AutoCAD 2010/2011/2012 DWG Format

[#1]

Hi, I  have a 3d topographic survey plan. I need to take sections at various locations and would like to know the best way of going about this.

I am used to working with solids and so would normally just take a section plane but this won't work as the 3d topographic survey plan I have is made up of polylines.

 Please could you  point me in the right direction?

Thanks

[#2]

Plain Autocad has no way to do it.

Civil 3D will.

[#3]

Thanks for your reply

[#4]

beg to differ - vanilla autocad isn't the easiest way to do it, but....

You could "LOFT" the contour lines to create a surface, use that surface to SLICE a solid cube that is larger than the site and then look at a cut section of the cube along a proposed alignment....  Where there's a will there's a way.  I wouldn't rely on it, but it could be done.  

This is from an exercise in the Mastering ACAD 2011 book....

[#5]

Show me, loft them, then post your result here with a cross section of E-W direction right in the middle of the site.

[#6]

I cheated & took the sample data from the book (exercise is in Chapter 22, page 714-719 of Mastering 2011....

I'll look at your example when I have time - not sure what will happen with the spaces in the contours from the text labels....

Procedure:

Loft makes you select each contour line in order - fine for the example, where it did not have a local high point....

Then have a rectangle below the "site" & extrude it up beyond the contours

Use the surface from the LOFT to slice the extruded box & only keep the lower portion.

THen I  set up a UCS on a y-z plane & created a rectangle on the east-west line & used slice again to cut the surface

Finally "FLATSHOT" the sliced plane to get a section.

I'll have to see how the heck to make it (Loft) work when the contours give peaks & valleys, versus an upslope gradient....

As I said, not my fiirst choice by any means but I was able to get a section line from the flatshot - see below.

[#7]

It all comes to LOFT problem, they will intersect, therefore the reason I said kiss Vanilla good bye to do this task.

[#8]

Try the full working 21-day evaluation of DotSoft's MapWorks Sections.  It's a low cost add-on to plain AutoCAD.

[#9]

I would generally agree.  It MIGHT be possible to create a sophisticated surface in sections and "UNION" together...  but by when you invest enough time in such a mundane task you've probably wasted enough $$'s to pay for the upgrade to C3D...  

Just wanted to point out that there may be a way - not exactly optimal by any means, but it could work - esp given that we don't know how complex the OP's data is....

Cheers!

[#10]

Or if not C3D then a 3rd party add-on capable of the task....