It's Friday, which is a great day to solve a fairly complex Alignment layout for the sake of bragging rights to your peers!
I have an old alignment that I know works on paper and solves to within a second that I need to recreate in Civil 3D, however, it has a couple of spirals in it that are bracketed by curves and it is proving a challenge to recreate in Civil 3D. I struggle with Alignemnt layout generally, and spirals just make it worse.
I thought I would post it here to see if anyone can crack this nut and post the commands\workflow used to solve it here.
Below is a Dropbox link to a PDF that has the geometry notes needed for layout. Curves are highlighted blue, spirals green.
I'm no guru by any definition of the term, but I think the solution is pretty simple.
Layout the incoming and outgoing tangents. Then use the Free Compound Spiral-Curve-Spiral-Curve-Spiral (Between two tangents) tool as shown in the screen capture. Since you don't have an incoming spiral just set the length to zero for the first spiral when prompted.
Neil Wilson (a.k.a. neilw) Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1 WIN 7 64 PRO HP Pavillion h8xt, i7 2600, 12 GB RADEON 6450, 1 GB http://www.sec-landmgt.com
That worked, only, it is making the delta larger in the first curve by a few seconds which lengthens the entire alignment by about 0.06'... This isn't a huge deal, but we get it to close on paper to within .01 using the same input criteria....