Hi Guys,
I am currently working on a Stream Restoration project and am really struggling to find a flexible solution for modelling natural river corridors.
My Landscape Architect has provided me with a set of 2d-Polylines representing the proposed river alignment as well as some embankment lines. (Spline.jpg)
My first attempt was to create a corridor with a cross-section consisting of some generic links targeting my polylines. Please see attachment (Corridor.jpg). Obviously it results in a total mess. So I tried splitting the corridor in multiple sub-corridors targeting different lines as suggested by Dana Probert in her class on Stream Restoration. (Corridor1.jpg) However, given the curvature of these lines, the corridor simply never works as expected.
Question #1: is there any way to create a ‘smart subassembly’ which would prevent those bowties? Ideally I’d like it to be able to connect to subsequent vertices of the targeted line. Maybe the subassembly composer is capable of doing such magic tricks?
Since the corridor approach didn’t work I tried adding the Polylines as breaklines to a surface without any other definition. To assign some elevation data I converted them to Feature Lines. The original 2d-Polylines have been set to Fit -> Quadratic though and Civil 3d just refuses to accept them as they are. So I’d go splineedit -> convert to spline and then Flatten to convert them to Polylines back again.
This way I can convert my Polylines to Feature Lines, assign elevations in the elevation editor and add them to an empty surface. After playing around with the mid-ordinate distance and interpolation values I end up with something usable but difficult to manage (Surface feature line.jpg). The Flatten command converts my beautiful splines to a set of interconnected lines and arcs, which aren’t that easy to control. And for all this effort the resulting surface isn’t as smooth as expected (Object viewer.jpg).
Question #2: is there a way to convert splines to feature lines, or better yet – add splines as breaklines to a surface and derive their elevation from a profile?
My current solution to this problem is converting the 2d-Polylines to splines, and then back to Polylines via Splineedit. This way I get a Polyline with tons of straight but short segments. I convert them to feature lines, assign elevations and add as breaklines to the surface definition. The resulting surface is super smooth. It just isn’t easy to modify because of the amount of vertices that have to be moved to do any adjustments.
Question #3: Do you know of any better ways to approach this subject? All of the methods I’ve tried would have worked perfectly with a simple corridor. It’s the curvature that renders them useless.
