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: 

River bottom surface from 3dpolyline sections?

22 REPLIES 22
SOLVED
Reply
Message 1 of 23
Yami72
3690 Views, 22 Replies

River bottom surface from 3dpolyline sections?

Hello,

 

Can anyone tell is there an easy way to create a tin surface from 3d polylines that are generated by actual measurements of a river/ditch or imported from Hec-Ras (River Analysis -extension)?

 

The problem seems to be that the triangels should be long and narrow (like the ditch bottom in the example) instead of normal triangels the triangulation method normally generates. (The triangels in the example are generated by 3dwin -program).

 

When using Hec-Ras one way to go around this problem is to interpolate sections (XS:s) with very short distance. Hec-Ras does the interpolation very well, but I would like to have a better solution without tricks with other programs. Also in the long rivers the result is a very large file.

 

I'm using C3D 2012

 

Anyone?

 

 

22 REPLIES 22
Message 21 of 23
bstab
in reply to: Yami72

I just ran across this thread.  Great idea Using Loft features to build a C3d surface. I am messing around with the process for a project now.  I know its an old(er) thread but has anyone figured out how to do this with guides opposed to paths?    I always get an error when selecting the guide splines that they do not intersect the cross section.  The issue that i am having with pathes is i'm trying match up the outer survey points with a LiDAR hydro breakline.  As you can imagine, the Hydro breakline generated from the Lidar is not very uniform and the channel width varies quite a bit.  I tried running the path method and works but somespots overlap the LiDARby 20-30 feet.  Meening I will basically be clipping the new channel surface down to this Hydro Breakline and burning into the LiDAR surface which will create a vertical wall inth overlapped sections.  Hence my desire to use the outer breaklines as guides.  

Before the surveyors gasp about my mthodologies, this final surface is going to be used for a HUGE 2D hydraulic model with 50-100 ft grid cells.  The section I am proposing to use LOFT surface is for model input at the upstream boundary.  All the topo within the area of interest is Multibeam cut into LiDAR. Typically i would manually draw breaklines and set grade betweento produce a sinuous channel surface.  In this case I have over 100 pts per cross section and would take weeks to do this manually. 

 

 

 

Thanks, 

Bstab

Message 22 of 23
autoMick
in reply to: bstab

Bstab, Not sure I have an answer, but I guess you need to decide which data are more representative at the point where you get the overlap. For a hydraulic model I would've thought that channel depth and sinuosity would be the most important factors, so the odd aesthetic in consistency would come second place.

If you posted some data of a good area running into a problem area someone might be able to come up with a plan as I'm having trouble picturing the issues.

Cheers

- Mick

Civil3d user in Australia since 2012.
Message 23 of 23
bstab
in reply to: Yami72

so basically i'm going to clip all of the 3d Loft data that falls outside of the hydro breakline because that is good LiDAR.   This means that there will be a near vertical wall when i interpolate between the in-channel and LiDAR surfaces for type 1,  and more gradualy sloped bank for type2.  

 

For this for this excercise, the general flow conveyance area will be captured pretty well and that is the most important factor as you mentioned.Things will be a little funkey on the banks and won't matter at the end of the day with a 50-100 ft grid size ( elevations will only be sampled to model mesh at 50-100ft).  

 

I have done some googeling around to try to apply the outer breaklines as guides so that the channel can expand and contract between surveyed sections to no avail but i am very happy with the possibilites of building river surfaces in this mannor.  I have spent countless hours drawing graded feature lines and flipping faces and building ras models just to interpolate surveyed cross sections. 

 

Thanks!

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

Post to forums  

Rail Community


Autodesk Design & Make Report