AutoCAD Map 3D General Discussion

AutoCAD Map 3D General Discussion

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1 Posts
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Registered: ‎03-27-2012
Post 1 of 4

Flood Trace help

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03-27-2012 01:27 PM

AutoCAD Map 3D 2012

I need someone to help me understand the Flood Trace procedure. 

I am trying to use it to calculate how long a spool of cable will reach with some resistances thrown in. For 

example, we have 3 utility poles (A, B and C) that we will string cable between. 1 coil of cable is 1000' long.
From pole A to B is 500' and from B to C is 500'. So 1 spool of cable will reach all the way from pole A to C
right? Right! (We are disregarding slack for our calculations.) Now what would happen if the cable was hung from
A to B and then had a 50' of slack hanging on pole B before heading towards pole C. Our coil of cable would now
be 50' short of reaching pole C right? Right! How do I get the Flood Trace topology procedure to tell me where
these breaks are?


This is a simplified example of what I'm trying to accomplish. Imagine hundreds of miles of cable and many, many
slack coils in my topology.


From what I read, the flood trace procedure should do what I want. I've figured out how to create a network topology with nodes. I've even done flood trace analysis using nodes as resistance but I can't seem to get it to spit out any results.


If anyone can help me work through this I'd appreciate it. Even if you could point me in the direction of some tutorials or examples that would probably be helpful. All the helpfiles I found were vague and kind of left you hanging at the end.

*Expert Elite*
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Registered: ‎11-13-2006
Post 2 of 4

Re: Flood Trace help

03-27-2012 02:36 PM in reply to: jreed03064

We just added 10% to the span lengths when I was doing it years back. Not only to you need to add in the slack but also the makeup for the attachments on the poles and it is all straight line or angle poles thrown it, vertical or cross arms?


Supportting the troops daily.
5 Posts
1 Kudo
Registered: ‎12-03-2008
Post 3 of 4

Re: Flood Trace help

03-28-2012 05:50 AM in reply to: Murph



I was trying to post as simple an example as I could to help me understand how the Flood Trace Procedure works. I didn't want to over complicate things with trying to post the exact specifics of my problem. We are taking into account sag between spans. However, that number is calculated before I enter it into the software. That 1000' coil I listed in my example is actually more like 20,000'. Someone has figured out that that 20,000' of cable (it's fiber optic cable) will actually only reach 19,000' (Not actual number) with sag added in.  Ok, so now we know how far it will reach right? Wrong! We also need to leave 150' maintenance loops at intervales. They'll also leave 150' coils of "tails" here and there depending on what's along the route. So that's 19,000'-(150' x number of maintenance loops) - (150' x # of tails) and you get the answer right? Wrong. Now you've reduced the cable length so far that some of the maintenance loops at the far end are no longer needed so you can add that footage back to your length. Confused yet?  To do the math manually, for one coil, really isn't that hard. It's just that we have hundreds of miles to do and the route is contstantly changing.


That's why I didn't want someone to solve my exact problem. I would just like to know how to get this Flood Trace procedure to work. From what I read it seems like it should do what I want. If I have a 50,000' route (polyline) with multiple slack coils along it (autocad points aka resistance) where will my new end point be if every time I cross a slack coil (acad point) 150' of my length is eaten up?  


Everytime I try the procedure I either get some vague error message or it will accept my input but not give me any results. I'm not sure if it's me or if Autocad is acting flakey.


Any help or link to tutorials or examples is appreciated.


Thanks. Jeff

AutoCAD Map 3D 2012
5 Posts
1 Kudo
Registered: ‎12-03-2008
Post 4 of 4

Re: Flood Trace help

03-28-2012 09:55 AM in reply to: jeff03064

I think I got it figured out. The problem was this. The software uses "links" and nodes (as resistance). In one test I drew a 10,000' polyline with just one start and end point. The software looked at the that as one link. Then I drew a 10,000' polyline with multiple vertices. This was also interpreted by the software as 1 link. With either of these situations when I tried to enter a trace value less than 10,000' I would get an error message. Obviously anything 10,000' and over and it would highlight the whole line. (Which doesn't help)


I ended up exploding my 10,000' polyline into lines and redefining my topology from that. Then when I tried to do a flood trace of 6000' it worked. It would trace it from the start point to a point where it couldn't successfully reach the end of the next full link. (It added links and resistance as it went)  

AutoCAD Map 3D 2012
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