Drone Technology in Architecture, Engineering and Construction

CHAPTER 10Working with 3D Models

Photogrammetry, reviewed in Chapter 9, can generate point cloud data and 3D mesh models, allowing for a variety of different uses depending on the project. These 3D cloud and mesh datasets allow for the extraction of site quantities and information useful for design and construction. They can also be used for incredible visualizations. From construction observation and administration to creating visual graphics and renderings, this chapter will provide an overview and specific examples of how to leverage 3D photogrammetric information.

Point Cloud versus 3D Mesh

Let's start with some simple definitions of a point cloud versus a mesh:

• Point Cloud. A point cloud, as defined in Chapter 9, is a point in space represented by XYZ coordinates and color values. While a point cloud looks solid when viewed from a distance, zooming in on point cloud data shows the different “points” of the cloud and the gaps between each point. Most point cloud viewers allow you to adjust the size of each individual point; a smaller sized setting shows more of the gaps while increasing the size causes each point to have greater overlap. Adjusting this size is easy to do with most software using a slider (Figure 10.1).
• 3D Mesh. A mesh is composed of 3D surfaces generated between, and connecting all, the points in a point cloud. 3D software programs interpolate and triangulate distances between the points generating a surface. In total, these surfaces create a solid 3D ...