topic Re: Creating a mesh/surface/solid from a topo survey? in AutoCAD Forum

Creating a mesh/surface/solid from a topo survey?

brady_grove — Mon, 28 Apr 2025 15:11:13 GMT

I am trying to convert a poly line topo survey to either a mesh, surface, or solid object. The topo has been imported with differing Z values per line. I am using AutoCAD to modify these poly lines to some sort of 3D object that is recognized by another software, and the other software will recognize any of these 3 objects properly. Is there any "easy way" to do this with the attached file?

Re: Creating a mesh/surface/solid from a topo survey?

pendean — Mon, 28 Apr 2025 15:27:15 GMT

You need to have used 3DPolylines to use the built-in tools to convert as you wish: it appears your DWG file only contains 2D Plines (well, there is one)

if you have access to Civil3D...

https://help.autodesk.com/view/CIV3D/2024/ENU/?guid=GUID-B58D3998-8452-41B1-BFA8-24293B41B094

Re: Creating a mesh/surface/solid from a topo survey?

brady_grove — Mon, 28 Apr 2025 15:58:37 GMT

I am using Civil3D and can convert those 2D lines to 3D, but the following tools still seem to have no effect: Convert to Solid, Convert to Surface, Convert to Mesh. Is there a different tool I need to be using? I still need the entire model to be one 3D object that the polylines are connected to make one large slope.

Re: Creating a mesh/surface/solid from a topo survey?

autoid374ceb4990 — Mon, 28 Apr 2025 21:25:30 GMT

If this will help, attached is your drawing converted to 3DFACES. I used a program that I wrote many years ago to convert contour lines to 3DFACES. What is the "other software" for which you are converting, and what type of file will it accept?

Re: Creating a mesh/surface/solid from a topo survey?

brady_grove — Mon, 28 Apr 2025 22:46:55 GMT

Oh wow, this is great. This seems to work perfectly! Is the process of changing contour lines to 3DFACES complicated enough that you built an entire program for?

The "other software" I am using is Slide3, a RocScience program. Which can import dxf files, so I got it from here. Thanks for taking the time to do that! I only expected instructions, not someone to commit real time to fixing my problem for me!

Re: Creating a mesh/surface/solid from a topo survey?

autoid374ceb4990 — Mon, 28 Apr 2025 23:45:42 GMT

Glad the 3DFACES worked for you. Many years ago (Apple II era) my wife (electrical engineer) and I (civil engineer and land surveyor) started our own company. There was hardly any software available, so I wrote my own. The code evolved over the years and was last written in 'C' code for AutoCAD R14. I never converted it to any of the later AutoCAD versions because I did not like their rental licensing. The code for converting contours and survey points to 3DAFCES and all the other mapping functions is probably several thousand lines now.