AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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Distinguished Contributor
nostupidquestions
Posts: 463
Registered: ‎11-17-2005
Message 1 of 6 (1,119 Views)

catchment area

1119 Views, 5 Replies
02-07-2011 08:44 AM

is the catchment area tool like the water drop tool except backwards? if i pick a point on my suface i would think it would give me the area that's flowing to it, like a watershed. it does this somewhat but it's not giving me what i think should be an acurate pline around the area. when i pick a point it should cover the whole side of a hill but it gives just a small area. i've picked a lot of places on the hill but the results are the same. i can't find any settings to maybe tweak the output.

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Distinguished Mentor
Civil3DReminders
Posts: 910
Registered: ‎03-24-2009
Message 2 of 6 (1,113 Views)

Re: catchment area

02-07-2011 09:02 AM in reply to: nostupidquestions

I'd look at the triangles of the surface to see if there are any flat spots that are causing the catchment tool to not make it up the hill. Maybe put a slope label on the triangle to see if it's flowing the correct direction towards the low point.

 

Christopher

Distinguished Contributor
nostupidquestions
Posts: 463
Registered: ‎11-17-2005
Message 3 of 6 (1,111 Views)

Re: catchment area

02-07-2011 09:12 AM in reply to: Civil3DReminders

i'm sure there a bunch of flat spots. it's quite a large site and the contours are derived from contour polylines. i was hoping there was a setting somewhere. i'm trying to find the top of the basin that's draining to our road. i just used the waterdrop tool and defined the ridge that way. my computer isn't powerful enough to use the watershed surface display. thanks anyway.

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Matt.Anderson
Posts: 2,909
Registered: ‎05-13-2005
Message 4 of 6 (1,069 Views)

Re: catchment area

02-07-2011 07:30 PM in reply to: nostupidquestions

If you review the user assistance, it is recommended that you use the water drop together with the catchment area to define the overall area.  

Matthew Anderson, PE
Product Manager
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Joe-Bouza
Posts: 4,966
Registered: ‎12-15-2008
Message 5 of 6 (1,052 Views)

Re: catchment area

02-08-2011 05:10 AM in reply to: nostupidquestions

Turn on the flow arrows of your surface to review the catchments area; if your surface definition has any vaugaries in it the catchments will pick them up. As Matt mentioned the tool works in conjunction with the water drop.

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People) Civil 3D 2012 & 2013
HP Z210 Workstation
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Note: Its all Resistentialism, so keep calm and carry on

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fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 6 of 6 (508 Views)

Re: catchment area

12-19-2012 04:40 AM in reply to: Matt.Anderson

"If you review the user assistance, it is recommended that you use the water drop together with the catchment area to define the overall area. " 

 

For years, this has been a tedious and very unelegant workflow suggestion. It is sophmoric and crude...

 

We need better basin analysis tools that think like an engineer and can see the drainage basin picture. We need surface drainage tools that allow the engineer to quickly achieve the level of basin discretization that the engineer is needing to achieve for the situation.

 

Usually this is aggregating the surface slivers these C3D surface routines typically produce for us, and expanding outward like the OP suggested.

 

Back to the drawing board for C3D programming...quickly get a surface algorithmist on this who understands what we have been frustrated with for years...

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
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