AutoCAD Civil 3D 2018 - Convert an AutoCAD Survey Drawing

By Justin Doughty

Civil 3D accepts a lot of different data formats, however sometimes we are just given a plain AutoCAD .dwg or .dxf file to work with and we have to make the best of what we are given. The guide below takes us through some typical steps of converting AutoCAD geometry into Civil 3D surface data.

So first would be to isolate any AutoCAD points, right click and select similar, then right click isolate objects:Convert these to Civil 3D points: 

(Hold down enter to speed up this process when converting the points).

Create a point group.

Create a new surface and add the point group to the definition. At this point you can assign contours/triangulation style etc. to check the output.

Then we can move on to any AutoCAD linework that needs to be included in the surface.

At this point you may be lucky and the AutoCAD drawing has layers already created for each set of features, however this may not be the case and you would have to manually select lines relating to each feature (roads, walls etc.) and put them on their own layer.

You will then be able to isolate each layer at a time and proceed with the below.

On the surface created, right click and add breaklines:Give this an appropriate name and then select the items to be included.

Then build up separate breakline definitions for each layer you need in your surface, as these can then be added/removed when viewing the surface.

So roads, walls, banking etc. This should give you a final surface with a set of changeable breakline sets.