Request about ditch generation

[MF]

First of all, thanks for your great software... it's very usefull and I use it almost every day for my hydraulic works.
My request: is it possible to add an option to align the internal edge of the ditch to the road bank base (2D or 3D polyline), following the projected alignement of the ditch bottom (i.e. not parallel to the terrain level)?
Thanks!

[Lars]

Hi!

I'm not sure what you are after. Could it be so that you would like to have the ditch bottom elevation to follow a 3Dpolyline (only vertically).

[MF]

Sorry, I try to better explain the question. Setting the vertical course of the ditch is not a problem, I use the existing command. I was thinking about a planimetric alignment of the ditch to a certain polyline (the "road bank base" in the attached image) following a given altimetric course. In other words, the ditch should be generated "locking" it on its "internal ditch edge" and not on the "ditch axis", as I do now. Thanks

[Lars]

Hmmm... I think I got it. Here is how I use to do things like that.

First I offset the Road bank base to get a parallel polyline. Then I drape it onto the existing ground.
Next step I offset the ditch bottom to two separate polylines with a safe distance to the left and right 20 meters or so then I triangulate these lines to a surface.

ok now I have a surface describing the ditch bottom, next step will be to create the ditch bottom. For that I use "Create longitudinal features" and setting the ditch bottom surface as target (remember to uncheck "Tick Marks") Using the offseted road bank base (draped) as alignment will generate a polyline at the bottom. If the ditch bottom surface elevation varies (as often) the parallel distance between road bank base and the ditch will also vary.

Then I offset the ditch bottom to get the planar part of the ditch bottom and finally I use the latter polyline and target that one to the existing ground. (also with "Create Longitudinal...")

To create tickmarks I use "Transverse lines..."  Done!


Was this to any help?

[MF]

It's a very good solution to my problem! I tried it and it works fine! Thanks

[Lars]

In the latest update (build 263, 2010-11-04) there is an option to set a slope for the intercepting surface plane (elevation) when using a plane rather than a surface. This is useful in the design process of ditches.

[MF]

It's an interesting option, I'll try it as soon as possible.
Thanks