Scenario - xyz points for river upstream & downstream with shots for ground, topbank, slopes, riverbeds.
somewhere in the middle of the river there is a topo for the road & as it crosses the river you have points of bridges - CL, edge of bridges, 1st approach, 2nd approach, abutment, etc.
My usual process is to draw breaklines along the topbanks, toe, river centerline for the river data.
for the road/bridge data, my breaklines are the edge of road, centerline of road/bridge.
in Land Desktop or Civil 3D if I mix these 2 sets of data I would get contour swirls near the bridge section due to the data for the riverbed under the bridge & the bridge data above it.
Is there a technique on how to draw the breaklines so that I don't have to separate the 2 datasets for road/bridge & river points and get a nice contour result?
I doubt it.
Could you not put the bridge on one surface and the river on a different surface. I don't know but think ihis might work. I would like to know the answer.
Mike
Normally, I do not contour the bridge. I will show spot shots along the bridge centerline. Usually the client wants to know about the river contours and perhaps the bridge clearance (Low Beam). I do not contour loading docks, etc. either. Contours are for the lay of the land, not manmade structures.
2 different surfaces, so time to make a second one for the bridge deck.
I never contour a bridge. I just show a few spot elevations. The contours shown will be on the ground.
Unless I know that the client is interested in the bridge surface, I leave the shots on the bridge deck out of the DTM. I use shaded linework to show the bridge deck so they know it's there, but no spot elevations or contours for it.
so I guess there is no easy way for this.
i also separate the 2 datasets for contour processing.
but sometimes it is a bit time consuming to separate them into 2 dtm because some shots from the bridge are needed by the river datasset for contouring - i.e. approaches, abutment & the road leading to/from the bridge.
the contour for the bridge is needed by the client for detailed engineering plans. usually the contours are just 1m interval.
in the early 1990s my former office was using a DOS based software - geocomp 9from australia and there was an option there for different types of breaklines - ER, slope, banks, overhangs, etc.
the guy that was processing the DTM then was using these various breaklines and the resulting contour was "logical". the software could more or less determine that the difference in riverbed & bridge elevation is due to overhangs and contour it appropriately.
this was the feature that i was trying to find in civil 3d.
thanks anyway.