AutoCAD Civil 3D

[#1]

Has anyone succesfully produced a slope analysis exhibit using LIDAR topographic base information with this version of Civil 3D? I have followed the instructions as best I can and have had no luck. I am using a trial version and this is a big factor in whether or not I will ultimately make the purchase. Any guidance would be greatly appreciated. Thanks

[#2]

I suppose the big question is exactly what you mean by "slope analysis"...

If you're talking about "slope arrows", then yes, C3D has always had this problem, as it insists upon inserting one arrow for every TIN triangle.  And this can create an absolute mess, if you're using LIDAR data to create a drawing, since LIDAR will tend to produce an incredibly large number of triangles, even when using the "Point File" option in C3D to create the surface.

Personally, I haven't found C3D very good at processing LIDAR data.  We use Trimble equipment, and have found Trimble Real Works to do a much better job of letting us prune down point clouds to a reasonable level, which we can then use to create surfaces in C3D.  The C3D Point Cloud tools have left us very frustrated, with nowhere near as much control.

But even if we use TRW to prune the data, we still end up with a lot of triangles.  And when C3D wants to put an arrow on every single triangle, we still get into a mess.

So not sure if I can give you any guidance....  Just commiseration, since we've encountered the same mess.

It's not so bad if you want to setup more of an "elevation" display, where various color gradients show the slope.  But the arrows are definitely a problem....

[#3]

Thank you for responding! The product I am looking for is a shaded/colored pattern of slope gradients.....

0-5%

5%-10%

etc.

The LIDAR topo already has contour lines generated. The source is not a series of point data. Does this provide a better description of the product I seek? There is a small example attached.

[#4]

Sounds like you're looking for a Slope display

You would need to generate a Civil 3D Surface, and apply a Slope Display to it (enabled in the Surface Style).  Then create a Surface Table that displays the Slopes.

You MAY also need to make sure you go into the Surface Properties, and create the correct ranges, as indicated below (remember to hit the downward-pointed arrow once you have the values set, to create the ranges).