Parrallel String on same x-fall

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Paul Wood
Posts: 59
Joined: Thu Jun 13, 2013 8:14 am

Parrallel String on same x-fall

Post by Paul Wood »

Is there a function, to parallel a string outwards, and keep it on the same x-fall from the crown... i.e. we have to widen a long stretch of road by 2 metres, and the x-fall from the crown changes rapidly from negative to positive and vice versa
Marc Ferguson
Posts: 133
Joined: Tue Dec 06, 2011 1:25 pm

Post by Marc Ferguson »

Try the option under

Survey => Extras => On Grade

This does exactly what you're asking

There is also another option under

Survey => TP Stakeout/Setout => Subgrade Strings => Subgrade Parallel
Steve Hunter
Posts: 1079
Joined: Mon Nov 07, 2005 7:30 am

Post by Steve Hunter »

In addition to Marc's method (thanks Marc, I never knew that option existed either):

Assuming you have some form of grade correction to consider (Minimum and Maximum Crossfalls), another feature to look at is the road widening macro under Design > Roads > More > Road Widening.

It will not generate a parallel string for you, but will give you some valuable guides as to what level to use in your design edge. You will get the direct extension of the crossfall, as well as the minimum and maximum xfall, assuming you have these criteria to consider in your final levels. You can then thread the vertical alignment of your new design road edge through these surfaces.

If you are using an Apply Many Function to design your new edge, you could transfer those design levels to your strings with a xfall to string modifier, or simply a xfall to tin on the extension of existing surface tin from the widening function if you only want the extension levels.

There is also a fairly sophisticated Overlay Design Utility under Design > Overlay, which allows you to evaluate the existing xfall, and generate the widening based on the results.

As with most things in 12D, there are several ways you can do something, which allows you to pick the one best suited to your project requirements.
Paul Wood
Posts: 59
Joined: Thu Jun 13, 2013 8:14 am

Post by Paul Wood »

Marc and Steve,

Both methods have worked nicely, thanks for your assistance
Glenn Coppard
Posts: 233
Joined: Thu Jul 24, 2008 7:44 am

Post by Glenn Coppard »

If you simply Parallel the edgeline or even an alignment, there is also:

Design -> Apply -> Amend VG [Amend Mode - Extend XFall]

Which you can select 2 strings (say surveyed CL & Edgeline) to extend from to your parallelled string.
zohaariz zoha
Posts: 1
Joined: Thu Nov 20, 2014 6:58 pm

Post by zohaariz zoha »

Thanks, found the tab.
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