In my previous post, I showed the process of creating 3D topography in SketchUp from a CAD survey with contour line elevations. In this post, I will take things even further, since my site plan also includes several roads and cul-de-sacs. The site I am working on has some really steep terrain, and while I could use the Drape command to simply impress the outline of the roads onto the terrain mesh, the result would be roads that wouldn't look even remotely realistic. A better option is to use some amazing plugins to simplify the process. Before beginning this process, you will need to download and install some plugins. The plugins used in this tutorial are the following:
Make Faces, by Todd Burch (free)
Instant Terrain, by Vali Architects ($7 per year)
Instant Road, by Vali Architects (free, $25 for pro version)
OK, let's get started!
To begin with, I import the CAD linework for the roads. In SketchUp, I then position the roads above the terrain, so that they align perfectly. This is what I see in my top view:
From there, I need to explode the grouped road linework. Right-click on the road and select Explode. Once it is exploded, it looks like this:
Now, I need to turn these lines into an actual face. Since I've installed the Make Faces plugin, this will be quite simple. With the road linework still selected, I go to Draw > Make Faces and in a few seconds I now have a road with a face:
For a moment I'm going to hide the road and just focus on the terrain. My next goal is to merge the road and the terrain, but one look at the terrain and you'll see that it is extremely complex - thousands of triangles which cause the model to generally respond really slowly. To add a road to this model, I need to be able to select a single mesh face, and this model has numerous partial meshes which comprise the terrain. This is where Instant Terrain comes in.
First, let's take a look at my terrain at an angle, to get a sense of its complexity:
The beauty of Instant Terrain is that it is quick, effective, and doesn't degrade the quality of the terrain model very much. To use this plugin, I first select the terrain model (it can be grouped, no exploding necessary) and select Plugins > Vali Architects > Instant Terrain >Make Terrain Over Objects. For grid spacing I select 10' (the smaller the grid spacing, the more accurate the final result will be, but it will take longer to create). Now I just wait for a few minutes, and this is the result:
I'm going to turn off hidden geometry for a minute to make things look a bit clearer. Additionally, I'm going to paint my terrain green so that the roads show up better. Next, I unhide my road. My model now looks like this:
It's now time to merge my road with the terrain. For this, I will be using Vali Architect's Instant Road plugin. This is one of the most useful plugins I've found recently - it has saved me literally hundreds of hours of labor, and does exactly what it says. First, I select my terrain mesh, then my road. Next, I go to Plugins > Instant Road > Road From Face(s). Once this is selected, I take a break and get some coffee - this process can take several minutes. Upon returning to my computer, I now have a graded road:
I am generally satisfied with the way the road and terrain have come together. Below are a few close-up images from the model: