How To Elevate Contours And Use Them To Build Existing Ground Surface Model

I was asked today how to convert imported Contour data for the Existing Ground surface into 3D linework and then into surface models for use in Cut / Fill calculations against a Proposed Model. I recorded the video below to show you how. This process works for both 2D and 3D imported Contours from CAD files or for 2D Vectors extracted from Georeferenced PDF files.

You may need to do some data prep / cleanup on the imported contour data, to create as many continuous lines as possible. You may also need to separate Index Contours from General Interval Contours and also separate the Contour Labels.

We do not recommend including the Text Labels in the surfaces as they will be converted to a 3D point at the insertion point of the text and will be added to the triangulation. Also if the contour labels have boxes drawn around them (or lozenges) then those should also be eliminated before elevating the contours as they will create “flat spots” in your models.

The processes shown in the video include

Advanced Select to separate out types of data
Elevate Contours using Contour Labels
Elevate Contours using crossing lines
Elevate Contours in a sequence based on an interval derived by looking at the contours.
Create Surface using the elevated contours
Using the Display Settings in View Filters to set unelevated linework to an alternate color so you can track the elevated vs non elevated linework as you progress through the process.

You can also use Set Line Elevation if you have a lot of contours that change elevation and direction a lot - that can be helpful

I hope that this covers this process step for you.

1 Like