Modeling Ditch that is at Toe of Fill Slope

[jgotsis]

For a Corridor Assembly/SubAssembly, how do I go about modeling a 3' wide and 1' deep triangular ditch that is at the toe of a varying width 2:1 fill slope.  See attached sketch.

Thanks.

[Joe-Bouza]

Have you looked into any of the OOTB daylight assemblies? There are several that make ditches.

[jgotsis]

Yes I have looked at the Daylight Subassemblies.  All ditches are in cut situation.  Please see my attached sketch again.  I am in a fill condition, and at the bottom of my fill slope I want a triangular ditch where the portion of foreslope is in fill, then into cut at 1.5:1 at 1' deep, then backslope would be a cut of 1.5:1 to daylight.  I have tried using a conditional fill slope with two 1.5:1 links, but have not had luck. 

[Joe-Bouza]

I see. I thought the GeneralDaylight could do that. You can probably put together some Generic links to get what you need

[ccoles]

That's interesting. Can you attach links to the end of a daylight assembly? I can see where that can possibly get you into trouble, though.

One trick I used recently was to use a standard daylight to determine the limits of fill, run a profile along that line, then use it for a width target to a generic link instead of a standard daylight, and use the existing ground line as my elevation target. Then build the rest of the ditch from that point, using a standard daylight at the end of it. It's not dynamic in the sense that it follows changes to the top of the slope, so I use this as I finalize the surface.

[peterfunkautodesk · Accepted solution]

Two ways this could be done. Use the Subassembly Composer and make a new SA or use generic links.

With Generic links you would:

1. Set a Marked point at the edge of the shoulder

2. Generic link to move 3' off the shoulder point (don't draw the link and use a point code that won't display)

3. Gerneric links slope to surface to find the far side of the ditch (don't draw the link and use a point code that won't display)

4. 2 generic links to form the ditch bottom

5. Link to marked point to add the slope

Cheers,

Peter Funk

Autodesk, Inc.

[jgotsis]

PeterFunk,

Your generic link solution worked! Thank you for the 5 steps you provided.  It took me a moment to realize when you use LinkToMarkedPoint, it does not draw a link to the marked point, but as long as you have the proper marked point named, it will work. 

Thank you again, and thank you all for your input. This Discussion Group is a life saver...

[neilyj666]

I'm a bit confused with Marked points - can you post  a screenshot of the completed assembly or a dwg with the assembly??

[jgotsis]

See the two attachements.  The pdf is my original sketch with Peter Funk's steps red-lined on it.  The .doc is the screen shot of how the assembly looks.  Hope it helps.

[neilyj666]

That's very helpful - many thanks

I've never been keen on having a ditch right at the botttom of a fill area; I prefer having it say 1m offset, could this be done with these steps (with additional links/points)??

Thanks

[peterfunkautodesk]

Yes, you would need to add one additional link. In the first link add the 1m offset and any slope that is needed on that offset link. If you don't want to do the math, then add an additional link at for the offset and slope. Then between steps 4 and 5 add the offset link for the flat (or almost flat) area at the bottom of the fill slope.

This is going to look very strange in layout mode.

I've also attached a quick PKT file that I made in 5 mins in Subassembly Composer. It will work on left and right (fill only) and has some parameters for the different elements. If you don't want the flat at the bottom, set the width to 0 (or remove a few of the links in the SA).

Cheers,

Peter Funk

Autodesk, Inc.

[neilyj666]

Thanks Peter - looks good......

[NicoDev]

What is the purpose of a ditch like this?

The ditch invert would undulate with existing ground - with high points and low points everywhere - and the ditch grade would be inconsistent.

[sboon]

Please note that you're commenting on a thread from three years ago.

Steve
Please use the Accept as Solution or Kudo buttons when appropriate

[fcernst]

The demonstration of problem solving logic using Corridor functionality by Peter Funk is definitely worthy of a bump.