topic Re: Switchback road - boundary intersect in Civil 3D Forum

Switchback road - boundary intersect

Crass — Tue, 18 Aug 2020 23:45:22 GMT

Hi - I am designing a tight radius driveway on a steep slope. Some weird stuff is happening as the corridor grades back to itself and it is not resolved very nicely. See the attached screenshot. Almost the entire road is in cut. Do you think this is an issue with my assembly? Any guidance would be greatly appreciated. Thanks!

Re: Switchback road - boundary intersect

Jeew-m — Wed, 19 Aug 2020 00:20:20 GMT

Hi,

Is it possible to attach the dwg?

Thanks

Re: Switchback road - boundary intersect

Crass — Wed, 19 Aug 2020 18:58:11 GMT

Hi. See the drawing file attached. Thanks for looking into this!

Re: Switchback road - boundary intersect

samir_rezk — Wed, 19 Aug 2020 19:58:50 GMT

Hi @Crass

The corridor assembly sampling was overlapping so I used the Clear Corridor Bowtie command to clear up the overlapping area. Also increased the frequency quite a bit so get a good sampling along the curvature. attached is the modified file.

Hope this helps,

Re: Switchback road - boundary intersect

neilyj666 — Wed, 19 Aug 2020 19:59:14 GMT

The slope is too slack on the right hand daylight - I amended it to 2V:1H.

I also split the corridor into 3 regions and increased the sampling distance to 5' from 25' as 25' won't give the detail required around the bend. For a final design I would copy the assembly, change the slope and sample distances for the copy and apply to the middle region only

Re: Switchback road - boundary intersect

Crass — Wed, 19 Aug 2020 20:49:30 GMT

Hello @samir_rezk Thanks! This is just what I was looking for. I haven't used the clear bowties tool before. This looks handy. I will keep the frequency in mind as well.

- Thank you as well.

It think the 0.5:1 side slope is a little steep for this site though.

Re: Switchback road - boundary intersect

Crass — Wed, 19 Aug 2020 21:11:47 GMT

@samir_rezk- I tried to replicate exactly what you did. I think I even selected the same Clear Corridor Bowtie point but my result is still a little wonky compared to your. See attached images. Anything I am missing in the process?

Re: Switchback road - boundary intersect

samir_rezk — Wed, 19 Aug 2020 21:21:43 GMT

Hi @Crass

In full disclosure, I also added all the top defining feature lines as a surface definition in the corridor properties/surface tab. The top links are not enough to have an accurate definition! The feature lines are imperative in giving the surface a linear definition, where the top links provide a sectional definition.

hope you get better results when you add them

Re: Switchback road - boundary intersect

neilyj666 — Thu, 20 Aug 2020 06:58:01 GMT

@Crass Yes 0.5:1 is steep and will depend on the strata present but the steepening technique can be useful if the strata is competent as it will reduce the excavation task but the bowtie clearance method suggested by @samir_rezk is the one to go with