topic surface edge at feature line with curve or arc in Civil 3D Forum

surface edge at feature line with curve or arc

demus72 — Mon, 24 Feb 2025 17:43:00 GMT

I have struggled with this for many years but when I create surfaces from feature lines with arcs, the tin doesn't produce consistent points along the arc. Please see attached image. When I create my feature lines, I don't insert PIs or elevation points along the arcs prior to adding these feature lines to the surface definition. What I end up doing it adding PIs or elevation points after the surface is created to make it define correctly. I'm hoping there is a setting that will aid in surface creation along arcs that I'm missing.

Thank you

Re: surface edge at feature line with curve or arc

RobertEVs — Mon, 24 Feb 2025 18:59:53 GMT

When adding featureline as breakline set mid ordinate distance to 0.01. Basically, what this does is forces a triangle between two points along the featureline that are a maximum of 0.01' perpendicular from your arc. Once added look at the triangles of your surface along the arc and this will make sense. Experiment with different mid-ordinate settings and see the results. You can do this by erasing the Arc, which will remove it from the build, then typing Opps and re-adding it back in with different mid ordinate setting