I need to create a truncated contour map based on data from a .asc file. I have connected the .asc file but there is no option for adding with query so I have brought the whole file in.
I then created a contour layer and added to map (all good so far) but when attempting to query this layer for my area of interest nothing appeared on screen.
I then did some manipulation of the sdf to create polylines at the contour elevation and tried to MAPTRIM but I stopped Civil 3D after having "not responding" for 15 minutes
The easiest way to accomplish this is to crop the .ASC before _MAPCONNECTing it.
For instance, Microdem is a free software able to create a georeferenced subset of a Dem.
I ended up creating the contour layer for the whole DEM, exporting to SDF and then importing to a new drawing.
I the used Boundary trim on small areas (about 7 in all) at a time to trim it and then queried to chage the elevation attribute.
I think it was crashing becasue I tried to trim everything at one (in an 80Mb file, 1m contour spacings = a lot of data)