2.4 - 3D Terrain Workflows

In this chapter we are going to explore working with the 3D terrain, making use of multiple tools covered in previous chapters. Using a site with steep topography, we will take the terrain that gets automatically imported, prepare the geometry, and then cut a hole for a basement from it.

If you wish to use exactly the same location as demoed in this tutorial, open the 2.4 – 3D Terrain Workflow_Start.axm from the FormIt Primer Part 2 Dataset.

1 – Start a new FormIt file, and import the 3D Terrain using the Location (SL) tool. Use the address “120 Arapahoe Ave, Boulder, CO 80302”, and select a region to import similar to the image below, making sure to include the octagon-shaped building. (If you are starting from the 2.4 – 3D Terrain Workflow_Start.axm file you can skip this step.)

Note: For more information on how to use the set Location (SL) tool, refer to the Part I chapter 1.1 – Set the Location.

2 - In the Layers Palette, turn on Terrain layer, which was automatically created when the Terrain was imported.

3 – The 3D terrain is imported as a mesh object, but before modifying it, the terrain must be converted to a FormIt geometry Object. This can be done using the Meshes to Objects (MO) tool:

  1. Edit the Terrain group, and select all of the faces in that group.

  2. Right-click one any of the selected faces to bring up the Context Menu.

  3. Select the Mesh To Object (MO) tool. The mesh will be automatically converted to a FormIt object.

  4. Finish editing the group.

Note: What is a mesh? In short, Meshes are lightweight representations of geometry, but Objects are more editable. To learn more, see the Meshes chapter in the Tool Library.

4 – The next step is to create a second object which we will use the cut the Terrain. For this example, we will create an octagon based on an existing building in the site.

  1. Turn off the Terrain layer.

  2. Draw a Polygon (Y) with 8 sides and a 30’ radius, and place it on the XY Plane.

  3. From the Top View (VT), move the octagon so that it is directly over the similarly-shaped building visible in the satellite image.

  4. Move the octagon up vertically 150’ along the blue axis (Z Axis).

  5. Turn the Terrain layer back on.

5 – Next, we will cut into the Terrain. For more information on how to use cut, and other advanced modeling tools, see chapter 2.2 - Advanced Modeling Tools.

  1. Extrude face downwards, so that it dips a few feet beyond the top face of the Terrain group.

  2. Use the Cut Geometry (CG) tool to carve the extrusion out of the Terrain.

  3. Delete the octagon we just used to cut the terrain. You should be left with just an octagon-shaped hole.

6 – Extrude the cut bottom face to adjust the basement depth. In this example, we aligned the base to the lowest point in the site.

7 – To experiment with a few more FormIt features, you can continue manipulating the terrain in the following way:

  1. Use the Extrusion Tool once again, to readjust the base depth to be about midway between the highest and lowest point of the octagon.

  2. Created a new material and applied it to the unpainted faces.

  3. Use the Tilt Face (TF) tool to create a softer transition between the base grade and the natural terrain. Now we have a nice platform to build our octagonal building on, based of the real terrain data of the site!

Note: To learn more about the Tilt Face (TF) tool, see chapter 2.2 - Advanced Modeling Tools.

Note: To compare your results to ours, check out the 2.4 – 3D Terrain Workflow_Completed.axm file from the Encode Model Data Set.

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