Since Dynamo provides access to the API, it can be quite useful in automating certain processes, such as placing, sizing, and rotating plants. But it can also be utilized as an analysis tool.

And Topography slope analysis is frequently required to determine which areas of land are buildable.

Jostein Olsen first wrote a blog post back in June on Analyzing topography slope with Dynamo, which was itself based on a thread at the Dynamo forum. His analysis was an excellent proof of concept and showed which faces of the surface were almost entirely flat.

But to do a more comprehensive slope analysis, I wanted to show a larger range of slopes. I also wanted to analyze the slope as percentage slope, so I modified the definition accordingly.

Here is the result:

And in plan, the slopes look like this…

The slopes are set to a color range, and color accordingly:

0% – blue, 10% – green, 20% – yellow, 33% – orange, 100% – red. And anything 100% (45 degrees) or greater is white.

Here is the definition:

The green group at the end will create an import so you can see the Topography coloring directly in Revit (though it will only override the import coloring in the current view).

And since this test/ example Topo is a fairly simple surface, I also tested it out on a much more complex surface…

It only took a few minutes to generate the Dynamo mesh (without the import geometry).

However, for some reason, sometimes the gray mesh overlaps so that you cannot really see the coloring. So I also ran a test with the import geometry.

Not surprisingly, creating all of the import faces took a bit longer (around 12 minutes), but the result is quite effective.