C3D TO HEC-RAS OUTPUT

[WheelerCJ]

Hello,

I have been asked to convert a C3D file (containing a surface) to HEC-RAS. According on various online forums/documents and this youtube video it should be a pretty straight forward process.

http://www.youtube.com/watch?v=DpMvnvoTKUA

When I carry out the export it creates the .geo file (HEC-RAS format). This is done by clicking OUTPUT > Export to HEC-RAS but for some reason it produces a file with no data.

I'm not sure what I'm doing wrong as the output process is pretty simple so if anyone has any experience in this please let me know.

Many thanks in advance.

[Hidden_Brain]

a few things to check: 1. are you selecting the sample line group, reach alignment, site, surface etc in the RAS export dialog? 2. are all sample lines contained within the surface boundary? 3. is the reach centerline alignment contained within the surface boundary?

[Wilbers2013]

Another thing to check is that you are sampling the correct surface.

[Anonymous]

In HEC-RAS use the import GIS format and point to the GEO file that you created with AutoCAD.

[WheelerCJ]

Sorry for the delay in getting back.

1. The export to HEC RAS dialogue wont let me select The reach alignment or sample line groups. I have a centerline alignment and a sample line group producing cross sections from this alignment. Is a centerline alignment different from a reach alignment?

2. Yes sample lines are contained within the surface. Would it matter if the Left/right offset on the sample lines meant they extended slighty outside the surface boundary on a couple of the cross sections?

3. Yes, the centerline alignment is within the surface boundary. Again this is is a centerline alignment not a reach alignment.

Thanks in advance for your replies.

[Wilbers2013]

Have you selected a site in the Export to HEC RAS dialog?

[WheelerCJ]

I have the option of 'Site 1' and 'none', site 1 is selected.

[Hidden_Brain]

#2 may be the source to your problem. Pull the cross section sample lines to be just inside the surface boundary and try exporting again. A better idea may be to extend the surface (add more data), since you may get vertical walls in the RAS analysis of the computed water surface exceeds the highest points of the cross sections.