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Civil 3D import for HEC-RAS 2

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Jajosk

Civil/Environmental
Mar 21, 2012
21
Took a dig at exporting a fictional river reach modeled in Cvil 3D 2011 to HEC RAS. As the attachment will show something went wrong somewhere as indicated by a discrepancy between geometric editor and the reach length table in HEC RAS:
Flow direction in Civil 3D is from 0+12.94 (U/S) to 0+116.6 (D/S) (Fig 1). Flow direction arrow in the drawing in HEC-RAS geometric editor (Fig 3) seems to be consistent with Civil 3D (left to right, 0+12.94 (U/S) to 0+116.6 (D/S)). However, the stationing seems to be reflecting the Civil 3D set up which is awkward for HEC-RAS given the flow n HEC-RAS is always from higher stationing to lower. The issue is more than just cosmetic - table for reach length confirms that the most upstream station is 116.6 and the most downstream is 12.94, which is in contradiction with the reach arrow in the drawing.
I have tried to reverse the alignment stationing in Civil 3D (Fig 2), and created a new .geo file but the drawing and table data in HEC RAS are unchanged. I have also tried to manually change the statioing of the XSs in the .geo file. That was disastrous as in the table, there was no value between the top row 116.6 and the next downstream XS, and there was a value for the bottom row 12.94. Any thoughts as to how to get the HEC RAS model to show 116.6 as the most U/S and 12.94 as the most D/S XS in both the drawing and the table?
Thanks!
 
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Yes, Civil 3D exports backwards into HEC RAS. [smarty]

You have to change it in HEC RAS. First Tools> Reverse Stationing, then GIS Tools>Reach Lines Invert Table>Flip Coord Order
 
Thanks LincolnPE. I did what you mentioned, but it still did not accomplish what I want. Before the routine you suggested the following were *correct* :
1. Direction of flow as per the drawing in the Geometry Editor;
2. Cross section station (L to R, looking from A toward B when the flow is from A to B)
3. Reach length table: Highest station number as the most U/S, lowest station number as the most D/S, distances between the station.
The following was *not correct*
1. Cross section station number as per the drawing in the Geometry Editor;

After the routine you suggested, the only thing I can see in the Geometry Editor was that the stations are now numbered R to L, but that is wrong since the direction of flow arrow remained unchanged.

Any other thoughts?
 
Let's see, I station the stream from 0+00 at the downstream end in Civil 3D. Export

Then in HEC RAS I need to flip the flow direction arrow, and get the cross section stationing to read Left to Right looking downstream by executing the two commands in HEC RAS I mentioned.
 
LincolnPE, you're a life saver [flowerface]
It all worked out this time, thanks much!!
 
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