AutoCAD Civil 3D

[#1]

i've got a ditch that has to be a minimum distance from the travel lane. it also has to have foreslope of 4:1 max. the ditch can move away from the travel lane at 4:1 but it can't get closer than minimum distance. i've got a ditch profile that varies quite a bit causing my ditch to be closer to the travel lane than the minimum required. what type of subassembly would you use to a) make the ditch follow the ditch profile and b) lessen the foreslope when the ditch gets shallow enough to cause it to get to close to the travel lane? is this a case for a conditional subassembly? thanks.

[#2]

You could easily make this using Subassembly Composer. 

Input Parameters:

Side: Right
Foreslope (Slope)

MinForeslopeWidth (Double)

Target Parameters:

DitchProfile (Elevation)

Start

P1 (at Origin)

AP1&AL1 (Slope and Delta Y, from P1, Slope = -math.abs(Foreslope), Elevation Target = DitchProfile)

Decision (AL1.xlength>=MinForeslopeWidth)

True side of decision: P2 (at AP1) and L1 (P1 to P2)

False side of decision: P2&L1 (Delta X and Delta Y, from P1, Delta X = MinForeslopeWidth, Delta Y = AP1.y)

Then either define the rest of the ditch with stock subassembly links in Civil 3D or finish defining the ditch using Subassembly Composer. 

[#3]

that must be in 2013. i'm on 2012.

[#4]

sub assembly composer was first available for 2012 C3D as a downloadable from the subscription center.

it's not part of the basic C3D package even in 2013 i don't think.

[#5]

Yes, sorry, it is with subscription for 2012, and downloadable with 2013 (you have to select from a checkbox during the installation, it does not download by default). 

[#6]

This is great! what if i already have and alignment for my ditch? i want the subassembly to follow the profile until it becomes to close to the travel lane, then i want it to follow the alignment.

[#7]

You can define a Target Offset parameter and have your point defined based on the Target Elevation and Target Offset (as defined by the ditch alignment/profile)

[#8]

Very impressive Kati,

how did you get so good with sub assembly composer?   Did you have some tough projects that required a custom assembly?

I've been looking into SAC on my own time, but it's very slow going.   I plan to look up your two classes and see if i can read up on your white papers.

Thanks, for the elegant solution to this problem.

[#9]

Thank you for the compliment Dan. I just like fiddling with "new toys" so I started playing with Subassembly Composer back when it was in beta testing.

Other than the two AU lectures (1st one is about starting from scratch and 2nd one is about starting from an existing PKT file) there is also a chapter in the Mastering Civil 3D 2013 book that is all about Subassembly Composer. And of course there are a few of us here on the discussion group that will chime in with answers as you try to figure a specific subassembly out. 

 Good luck with figuring it out! 

[#10]

it will be a huge time saver if i can learn it. something to do over the holidays.