Community
Civil 3D Forum
Welcome to Autodesk’s Civil 3D Forums. Share your knowledge, ask questions, and explore popular AutoCAD Civil 3D topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Intersect Surfaces

5 REPLIES 5
Reply
Message 1 of 6
sdevin
335 Views, 5 Replies

Intersect Surfaces

I have a water surface profile along a river from which I have created a C3D surface. I would like to intersect this surface with the existing grade along the channel bank to define the floodplain limit using a 3dpolyline I suppose. Is there any way to do this. I have tried creating a composite surface by pasting each surface but this didn't work. My water C3D surface extends under a portion of the existing ground surface and I would like to clip this portion.

Steven C. Devin, P.E.
Consulting Engineer
Civil 3D 2007 SP3
Dell Precision 670
Dual Xeon 3.2 MHz
3 GB RAM
Nvidia Quadro FX3400 256MB
5 REPLIES 5
Message 2 of 6
jwedding
in reply to: sdevin

Two options:
1. Use a corridor that daylights with an almost flat projection. Works OK
until you get into the bowtie areas.
3. Use a corridor with flat links that will extend out beyond the surface
interface. Create a surface from this, then run a volume analysis. Then draw
only the user defined contours and set only the 0 contour to show. Then
explode the volume and you have a polyline. Project that onto the EG and
you'll have your floodplain.

How's that RAS tool working out for you?

--
James Wedding, P.E.
Engineered Efficiency, Inc.
Civil 3D 2007
XP Tablet, SP2, 2GHz, 2G
www.eng-eff.com
www.civil3d.com
Message 3 of 6
sdevin
in reply to: sdevin

The HEC-RAS tools are great! I'm just trying a new way of presenting the data. I was able to essentially freehand the water boundary from the HEC-RAS tools but now I am trying to delineate a boundary that is 1 foot above the flood elevation. I'll give your second suggestion a try.
Message 4 of 6
jwedding
in reply to: sdevin

If you make the surface then just perform a datum edit, you should get the
1' freeboard line with no more work.

Glad to hear it's working for you.

--
James Wedding, P.E.
Engineered Efficiency, Inc.
Civil 3D 2007
XP Tablet, SP2, 2GHz, 2G
www.eng-eff.com
www.civil3d.com
Message 5 of 6
sdevin
in reply to: sdevin

I copied my water surface surface and then raised it one foot. However, I am still not sure how to make the new surface daylight into the existing ground. If I were to create a new profile that is one foot above the water surface profile I could perhaps build a corridor as you suggested but this also has problems. My river alignment consists of many segments connected by PI's with no curves. HEC-RAS didn't like it when I used curves. (Each end of the alignment appeared to be connected by a chord.) When I've tried to label offsets with stations and elevations I realized that there a blank areas because of the angle points on the alignment (there are blind zones where there is no stationing except at the alignment centerline.) I haven't made the corridor yet but I really wonder what will happen with these blind zones.
Message 6 of 6
jwedding
in reply to: sdevin

If you have the surface, use the volume surface technique to get the 0
contour and go from there.
--
James Wedding, P.E.
Engineered Efficiency, Inc.
Civil 3D 2007
XP Tablet, SP2, 2GHz, 2G
www.eng-eff.com
www.civil3d.com

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Rail Community


Autodesk Design & Make Report