Help! Surface Generation based on Contour Lines has spots that go as far as 0 Elevation

[mrenstra1]

I did MAPIMPORT from a LIDAR data to import contour lines for my drawing. It has 2m intervals and as far as I checked, the right contour polylines has an elevation around 1000m and I don't see any overlapping lines. Yet when I generate a surface based on the contour lines, it has spots that are clearly anomalies (see attachment 1)

I've tried quick searching polylines with the lowest elevation and I've seen none. Anybody have an idea what went wrong and how do I fix this? Thank you in advance.

[idoQEYMP · Accepted solution]

It'd be hard to tell what is causing this without looking at the dwg. If the incorrect elevation values that are inserted are 0, since you are clearly much higher everywhere else, as a remedy you can try to set the surface build settings to exclude elevations that are below ___(m) (use a value of elevations that is clearly outside the elevations extents of you project, but above 0). You'll find the setting in surface properties, definition tab, under build.

[Jerry_Barnes]

Copy and paste this link into your browser, watch the video, and see if it answers your question: Webinar: Importing GIS Data Into AutoCAD Civil 3D - YouTube.