AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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jhoff
Posts: 25
Registered: ‎05-15-2004
Message 1 of 19 (1,565 Views)
Accepted Solution

Using negative cut slope

1565 Views, 18 Replies
10-30-2012 09:31 AM

I have a simple driveway corridor along a steep hillside.  For cut, I would like to have a negative slope away from the shoulder edge.  I have tried numerous approaches and all 'cut' reverts to positive.  I searched and found no clear answer.  It's such a short driveway, I can 'fake' it in, but I would like to calculate quantities.  What is the answer? Why is this so complicated? Thanks.

 

Using 2012 sp1, 64bit, windows 7

Hello,

 

It may not be overly apparent - but if you use LinkSlopetoSurface and in Subassembly Properties, specify Fill Only, the Subassembly will project a "downward" slope, in a Cut condition.  

 

I've attached an image that shows something similar.  Note the Subassembly Properties (Fill Only) and how this parameter is interpreted in the Corridor Section Editor.

 

Hope this helps.

 

Andrew

 

Fill Only.png

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sboon
Posts: 2,226
Registered: ‎11-08-2005
Message 2 of 19 (1,560 Views)

Re: Using negative cut slope

10-30-2012 09:54 AM in reply to: jhoff

In the programmers terminology "cut" is always upwards, and there is no such thing as a negative cut slope.

 

How are you building this slope - grading objects or corridor?

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jhoff
Posts: 25
Registered: ‎05-15-2004
Message 3 of 19 (1,550 Views)

Re: Using negative cut slope

10-30-2012 10:28 AM in reply to: sboon

I'm using a corridor. 

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sboon
Posts: 2,226
Registered: ‎11-08-2005
Message 4 of 19 (1,546 Views)

Re: Using negative cut slope

10-30-2012 10:35 AM in reply to: jhoff

There are several subassemblies that will allow you to force a downhill slope from the road shoulder to a specified distance or elevation, then back up to the ground surface.  A drawing or sketch showing what you already have and what you're trying to achieve would be helpful.

Valued Mentor
Valued Mentor
sjg
Posts: 534
Registered: ‎09-29-2010
Message 5 of 19 (1,539 Views)

Re: Using negative cut slope

10-30-2012 11:24 AM in reply to: jhoff
You could use the Generic LinkSlopetoSurface
Steve Goessling
Land Consultants
Civil3D 2013
Windows 7, 64 bit
Intel i7 2600 @ 3.40Ghz
16 GB RAM
Nvidia Quadro 600
Contributor
jhoff
Posts: 25
Registered: ‎05-15-2004
Message 6 of 19 (1,523 Views)

Re: Using negative cut slope

10-30-2012 12:37 PM in reply to: jhoff

Well, I tried that.  It will work if I specify only cut, but it won't display.  See attached.  I just need to specify a simple bench cut.  Suggestions?

Valued Mentor
Valued Mentor
sjg
Posts: 534
Registered: ‎09-29-2010
Message 7 of 19 (1,508 Views)

Re: Using negative cut slope

10-30-2012 01:16 PM in reply to: jhoff
Did you select the target in the corridor for that link? Did you change the link or point code name? If so, is your code set style set to display that link name?
Steve Goessling
Land Consultants
Civil3D 2013
Windows 7, 64 bit
Intel i7 2600 @ 3.40Ghz
16 GB RAM
Nvidia Quadro 600
*Expert Elite*
sboon
Posts: 2,226
Registered: ‎11-08-2005
Message 8 of 19 (1,494 Views)

Re: Using negative cut slope

10-30-2012 01:36 PM in reply to: sjg

LinkSlopeToSurface may not be the appropriate choice for this situation. If you want to enforce a downhill slope to a surface which is a cut situation then there is a workaround using the DaylightGeneral sub to do this.

 

DaylightGeneral builds a series of temporary links out to a test point, which is normally at the outside corner of a ditch.  If this point is in cut then it continues to build the rest of the ditch and daylight.  If any part of the temporary links are in cut, but the test point is in fill then it works backward along the links until it finds an intersection with the surface and daylights there.  For your scenario I would put the test point at the end of the first temporary link, and make that link at the correct slope but very long so that the test point would always end up in fill.

 

Distinguished Contributor
apweng
Posts: 265
Registered: ‎12-10-2003
Message 9 of 19 (1,482 Views)

Re: Using negative cut slope

10-30-2012 04:03 PM in reply to: jhoff

Hello,

 

It may not be overly apparent - but if you use LinkSlopetoSurface and in Subassembly Properties, specify Fill Only, the Subassembly will project a "downward" slope, in a Cut condition.  

 

I've attached an image that shows something similar.  Note the Subassembly Properties (Fill Only) and how this parameter is interpreted in the Corridor Section Editor.

 

Hope this helps.

 

Andrew

 

Fill Only.png

Valued Mentor
david.zavislan
Posts: 282
Registered: ‎10-31-2006
Message 10 of 19 (1,459 Views)

Re: Using negative cut slope

10-31-2012 08:25 AM in reply to: jhoff

The default daylight subassemblies have conditions that do not allow negative slope values.   Using Subassembly Composer you can create your own daylight subassembly that does not have any restrictions on slope value. 

 

Attached is an example subassembly that I use for these conditions.

David Zavislan, P.E. | Wood Rodgers, Inc.
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