One of the ways we are using the model in the field on the Autodesk project is total station layout. Rather than rewrite an explanation of what we did, here is what our Assistant Project Manager put together to communicate the process.
0 1 S I T E S U R V E Y
It all begins with a site survey (or in this case, an integrated site survey and laser scan). Once the survey and scan are complete, they are imported into the model, to provide both existing conditions and tie the model into real world coordinates. The laser scan allows the team to understand the exact geometry in the existing structure so that as they lay in components, there are fewer size inaccuracies. In short, the laser scan is the world’s best as-built; down to a fraction of an inch.
0 2 L A Y O U T P R E P
First, the team must decide what geometry will be extracted from the model and marked in the actual building: floor opening, partition locations, penetrations, lighting fixtures, critical ductwork, and the list goes on. After the components are selected, points are marked in the model. These points become the basis for layout once in the field. Once all points are identified, the information is imported into a robotic total station, layout equipment. Since the process began with a site survey, the total station can translate the points in the model to points in the building.
0 3 C O N S T R U C T I O N L A Y O U T
Tocci, armed with a model containing the latest (and final!) design content, begins the layout process. First step: establish the same control points that were used during the initial survey/scan of the building. Once the points are established, the layout team begins marking all points that were preselected in the layout drawings. As these points are marked, the design team takes a few choice points to check and compare with their design – simple check and balance. Once the architect blesses the layout, all points are connected, lines are snapped and the layout is complete and ready for construction.
0 4 T H E B E N E F I T
Layout can be completed prior to any interruption from construction activity, allowing for a greater level of detail, not to mention that it is being extracted directly from the team’s model.