Creating Surface from DEM and editing it

nasko88 — Sun, 14 Sep 2025 04:25:07 GMT

Hi,

I've made a lidar scan of a river (around 2.5km long) and now I have a DEM file of the terrain. We've also measured the river points with GPS reciever.

I am working with Civil 3d 2025 and want to create Surface from it, so what I do is in Surface into DEM files I select my DEM. So far so good, evrtithing is going smootly. Now I've created a feature lines from points, measured with GPS.

Now I want to insert the featurelines into Surface (with DEM inserted already) as a breaklines. When I try to do that it comes error cause the breaklines crosses triangles of the DEM file. So what should I do and what are the best practices working with DEM? And how I can easyli edit DEM Surface in areas where point classification failed and should be manually flattened?

P.S. I am attaching some pic, where it can easily see that the Surface has to be editted. With Red are the featurelines which I want to insert as breaklines.

Re: Creating Surface from DEM and editing it

Jeew-m — Sun, 14 Sep 2025 11:01:10 GMT

Hi,

THIS would help you.

Re: Creating Surface from DEM and editing it

Joe-Bouza — Mon, 15 Sep 2025 14:27:57 GMT

I would go with composite surface.

Blank EG

FL Surface

DEM Surface

Paste DEM into EG, then FL surface

topic Re: Creating Surface from DEM and editing it in Civil 3D Forum

Creating Surface from DEM and editing it

Re: Creating Surface from DEM and editing it

Re: Creating Surface from DEM and editing it