ditch bottom to alignment or feature line

[bf]

C3D 2014. Assembly with a road shoulder and DaylightBasin subassemblies. I want to target the 2' ditch bottom, at a desired slope, to a feature line or alignment. Have generated a profile of desired ditch bottom and sections of assembly.  I see in help where you can but it doesn't tell me how.  Attached is assembly.

[bf]

and whoever writes the help files should write them for folks like me that don't use all the features all the time.  step by step, descripive.  Act like you are writing the program.  No one I know likes the help. 

[doni49]

You haven't provided enough information to be able to construct this ditch.  Take a look at the following edit of your image.

The yellow line is something I sketched to represent an EG surface.  So how are you determining the location of the ditch?  Do you know the A dim (the ditch foreslope distance)?  Does that not matter but you need a specific ditch back slope (dim b)?  Or maybe the ditch depth (Dim C) is more important.  And once you've decided that, you need to fill in one more element (any one of the previous items) so that you can go from the ditch back to the EG (or possibly some other point whatever that is). 

EDIT:  I forgot one other piece of info -- the ditch backslope SLOPE.

[bf]

Thanks for replying Don.  I would like to maintain my foreslope and have my ditch bottom follow an irregularly sloped ditch (profiled by a feature line or alignment.

[doni49]

I know how I'd do it if I were using a custom sub-assembly but I don't know how to do it with the stock assemblies (or even it can be done). 

[bf]

Yea, yesterday I made a custom from polyline and attached to a stock subassembly.  Didn't work the way I liked.  How would you do the custom?  I have something else to try.

[doni49]

Subassembly Composer is a windows application that comes with C3D. 

I'll attach something I wrote for people in my office along with the example SA that I used.  Hopefully it'll help you understand SAC.  Beyond that I'd suggest that you google the term "SAC TUTORIAL MERCIER".  Kati Mercier (a frequent poster here) made a tutorial that I found most helpful when I was trying to understand it.

Once you get the hang of it, it's an extremely powerful tool.  I'd just caution you to try and use a stock SA when possible.

The website won't allow anyone to post files created by SAC (yes -- the Autodesk website won't allow you ot post a file created by an Autodesk product).  So SOP around here is to rename it as a zip file -- then the person downloading it saves it but changes the extension from zip to pkt (the extension that SAC uses).  So rename the zip file with a pkt extension before trying to open it.

HTH and good luck!

EDIT:  that doc file isn't the right one.  I'll have to see if I can find it.

[doni49]

Ok found the right one.

[bf]

where is subassembly composer?  I can't find it anywhere. 

[doni49]

Start Menu>Autodesk>Subassembly Composer Version

[doni49]

BTW...

Here's an EXCELLENT video on SAC from Kati Mercier.

http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2011/autocad-civil-3d/create-subass...