Contour Manipulation for Grading

How do the architects on this Forum produce professional grading plans in SketchUp?
Obviously the Sandbox Tools will be a big help.
Yet, ultimately I need to be able to produce a detailed grading plan that will communicate to a surveyor and contractor solid new contour lines superimposed above the dashed existing contours - old school formatting.
It’s easy to turn the existing contours into dashed lines of course.
But is it possible in SketchUp to create brand new contour lines and manipulate them?
Maybe I’ll be able to use the Bezier Curve Tool Extension for this.
But so far in my own search I’ve not found a specific approach.

I need to be able to make a drawing like this one:

“SketchUp and Daniel Tal”
Headed to Google this

1 Like

Yeah, he’s the guy to look to.

If you have the contours, Sandbox will produce the land form. If you have the land form, a series of planes at contour elevations intersected with the form will produce the contours, at least a version of them.


There’s a good extension called “Contour Maker” which makes contour lines very rapidly, at any increment.
It doesnt appear to set their height according to a datum, however, so you have to be careful about where your Component’s origin is set to. Also, the extension won’t add labels.

[Plugin] Contour Maker v1.6

Then you have “simplify contours” as another extension as well if you are getting lines that have too many edges or you want to simplify them.
I usually make contours at 200mm increments, then colour them differently so every 5th contour (1m) is darker (or you can use another layer and then make it appear thicker using LayOut).

Producing a really nice contour plan in SU+LO is, unfortunately, quite difficult!!

First, the Contours generated by SU cannot be smoothed into nice curves to represent actual “organic” landform (similar to your example above) since the SU surface is typically quite angular or blocky. Therefore the contour lines show the angles (and any other small steps/gaps/etc) will look like a lot of zig-zags.

Second, it’s very difficult to label the contours. The Edge anotation tool in LayOut only appears to give the Length of an edge, not the Height of the edge/point or any other information that could be useful (gradient/slope of edge, for example).

1 Like

I have done something like that:

-Google map showing terrain as a background
-Viewport for boundary line and thicker contour lines (cropped a bit wider than boundary line)
-Viewport with thin contour lines cropped to the boundary line
The rest is just text and lines added manually

Terrain comes from google maps, stretched to match onsite measurements,
Contour lines where created using plans intersecting the terrain as mentioned by @RTCool

Thank you.
Very helpful

Theres also an extension called Height Above Datum, if you want to add labels showing the height of the contours (in sketchup, not layout).

And Gradient Tools can tag an edge or face with its slope/gradient label.