Resizing river sections

[ytzvib]

Hi,

I have 1000' sections in flood and river analysis and I want to change it to 2000'. The only way that I can see is to delete the sections and restart. I wanted to know if there is an easier way.

Thanks in advance

[Alfred.NESWADBA]

Hi,

are you referring to the interval of the section lines (sample lines) or the width (right & left) of the sample lines or section view profiles?

My first guess is you are looking for the width of the sample lines, in that case you can navigate to the sample line group in the Civil 3D toolspace => right-click ==> "Properties" ==> go to tab "Sample Lines".

In this list select all sample lines (select first, scroll down, and <Shift>+Click to the last row)

Now you can edit the left offset and right offset for all selected rows

- alfred -

[ytzvib]

Thanks for the response.

I'm referring to crossections using the flood and river analysis for civil 3d which is an add on to help automate some of the things done in HEC-RAS.

[Anonymous]

The HECRAS feature in auto cad uses Sample Lines to generate cross sectional profiles across your river alignment using a specified surface. You can automatically generate sample lines or your can select existing poly lines instead. If you are using existing poly lines you will need to redraw them to the correct size you would like. If cad is generating your sample lines, you have the flexibility to extend them like the previous post suggested.

[ytzvib]

Hi,

Please see the photo I do not have any centerline alignments but I have my river crossctions.

Thanks

[Anonymous]

You may already know all of this but If you aren't that familiar with the process (and I am definitely no pro either), there are some online tutorials you can search for in google video or youtube to get you started. Start with "Hec RAS civil 3d."

Essentially to use Export to HEC RAS tool in C3d you need to:

1. Have a working surface in your drawing with the existing surface data. 

2. Define your stream center line and make it an alignment. I use the center line alignment type.

3. Define the cross sections by using the Sample Line Tools and choosing "Select Existing Polylines" in the drop down menu. You will then select the poly lines you would like to use as your cross sections.

4. Choose Export to HEC RAS

5. Select which surface you would like to use, the name of your reach alignment (from step 2 above), and the sample line groups (your poly lines from step 3.)

If your polylines/cross sections need to be longer, they will need to be edited using the 2d drafting features of cad.

[ytzvib]

Hi,

Thanks for the reply but I'm using Autodesk® River and Flood Analysis Module which has a lot of the functionality of HEC-RAS there is an option to automatically add crossections and I wanted to know how to resize them once it was created. When it is done using the module you can't use an alignment it has to be a polyline.

[doni49]

The yellow lines you see are the aforementioned "Sample Lines".  Select one of them and you should see a contextual ribbon appear above.  There you should see "Group Properties".  Choose it then select the Sample Line again (I don't know why it doesn't remember the fact that you already selected it).  Now you'll see the same dialog box that @Alfred.NESWADBA referenced.  Follow his instructions from that point.

[ytzvib]

Hi,

Please see the image below again these sections where made using Autodesk river and flood analysis (see the ribbon)as you can see in my properties palette they are 3d polylines.

[Anonymous]

You should take this thread down as it answers nothing.  2018 River analysis does not use alignments and section.  Wow?

[ytzvib]

Hi,

That's exactly why I didn't get an answer to my questions everyone keeps on referring to sample lines of alignments when they have nothing to do with what I'm asking.

[ChrisRS]

@ytzvib, I think I can help. RFA does not have a tool that will help you with this or automate the process, but it can be done pretty easily. If you have a lot to do, it will be tedious.

RFA can get elevation information from Civl 3D surfaces. Other than that, no Civil 3d objects appear to be used by RFA. I do not know what mechanisms RFA uses, but I do not need to know that to use RFA.

Any sufficiently advance technology is indistinguishable from magic -- Arthur C. Clarke

River and Flood sections are represented by yellow 3D Polylines. You can modify these polylines pretty much anyway you would like. Use can drag the end points to a new location; draw a reference line and extend or trim the "section lines" to it; etc.

In your case you could scale each section line (individually), using the midpoint, by 2. This will not work for angled sections. 

Once you have modified the yellow polylines you need to update the cross section geometry by recutting the changed sections:
           River tab, [Create Section] [Recut Section]

You can recut section by section or recut all sections at once.

If you have widened the sections, you may need to resize the Section views.

          River tab, [Section Geometry] [Resize Section Views]

Finally, adjust the Section ID Locations.

          River tab, [Link Section] [Update Section ID Locations]

Good Luck!

Chris Stevens