Curved break lines create elevation points in surface lower than point data on either side - Survey C3D 2020

[brittpiap]

Does this happen to anyone else?

I have curved survey figures and feature lines to add to surface

and the program creates elevation points along the curve

THAT ARE LOWER THAN the Point Data on either side of the curve.

Which makes me have to go in and modify point to a more accurate elevation.

Why does this happen? Where can I go to uncheck any command that allows this to happen?

Usually it's within a foot of difference.

Thanks for your time. 

[Udo_Huebner]

How curved and long are the curve segments of your feature lines - are they semicircular?

Could you upload a simple example drawing? I know the elevation problem with slopes with feature lines with semi-circular curves. It helps to add some manual elevation points up front.

[brittpiap]

I solved my current 4 foot problem so that's why I edited the question.

That was user error! Dang.

I always define my surface with point group first and then add the breaklines after that.

So I really have no idea where this alternate data comes from.

The area this usually happens along are on curb returns.

It took me a while to figure out what the problem was the first time

but now it's something I check for on object viewer every time.

It's a real bummer to have to edit curb return points on large municipal topo projects.

[Anonymous]

Yeah, check the order of build operations in surface properties. Use the arrows to move things up in the list to account for them first. Boundaries are pretty much always last.

I think survey figures and feature lines use 3D curves. They want to force thing tangent in and out of the curve. so you can have situations where the curve is sagging down vertically. Adding supplemental data (points) on the line between points on either side of the line that is at the elevation that you'd expect or had measured would be one way to solve it, if this is happening.

Sometimes finesse is called for, sometimes methodical plodding along. And sometimes you have to beat C3D into submission. This would be one of those times.

[brittpiap]

Ha ha. Yes. Sometimes I have to beat it into submission.