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.