Issue with quick profile

[mwaPT95E]

I have a 3D polyline (stream thalweg) running along a surface (topo-bathymetry). When I plot a quick profile of the 3d line, I see an expected profile of the thalweg over the stream channel bottom. However, the profile graph also includes a second line, referred to as the "3DEntity Profile". This entity profile appears to show a 'hole' in the surface, where the elevation drops from 1459' to 0', before jumping back up to 1460'. It looks like a giant wedge in the middle of the profile line.

My confusion stems from the fact that the surface profile line does not have a 'hole' in it, nor does the surface itself. I have doubled checked to ensure the surface topo is good and that the thalweg polyline nodes are snapped to my survey points.  In the image below, you can see the two lines are nearly identical except for this weird 'hole'. 

What is going on here? Am I over thinking something, or is there an error in my surface?

Thanks!

[Matheus-Lima]

Hi @mwaPT95E!

The surface profile is created following the polyline in PLANE and Civil 3D gets the elevation from each point from a surface. So if your surface is ok (apparently is) there will be no problem here.

On the other hand, the 3D entity profile is created following the polyline in PLANE and Civil 3D gets the elevation from the polyline vertices. If you click on the 3D polyline and see it in the object viewer, doesn't it have a hole in it?

Cheers,

[jmayo-EE · Accepted solution]

I would first open the surface, get into a 3d view, displaying the TIN triangles and see if the surface is running to elevation zero. If so I would correct the objects forcing the TIN to elev 0.

If that step did not show anything at elev 0 I would then temporarily turn off or remove any surface boundaries to again see if the surface went down to elev 0. The profile may be ignoring a TIN Hide Boundary.

John