Sedco 707 Columns
The above is a 3D model created in AutoCAD by Scan Tech, LLC of the columns on the drilling rig Sedco 707. The columns were drawn based off of laser scan data and original as-built drawings provided by the customer.
What is Laser Scanning?
In principle, 3D laser scanners work by sending a laser beam all over the field of view. Whenever the laser beam hits a reflective surface, it is reflected back into the direction of the scanner.
To determine the position in space of the captured object, the laser scanner uses polar coordinates which consist of the horizontal angle, the vertical angle, and the measured distance relatice to the laser scanners position.
The horizontal angle is given by the rotation angle of the laser scanner about it's vertical axis, measured by an angle encoder. The vertical angle is defined by the rotation angle of the reflecting mirror which deflects the laser beam on a circular track through space. This angle is measured by a second angle encoder. The distance sensor measures the distance from the laser scanner to the hit object. In most cases either Phase Shift Measurement or Time of Flight Measurement (=Pulse Measurement) is used to determine the distance.
Additionally to the pure position in space, the laser scanner determines the reflectivity of the captured surfaces by measuring the intensity of the received laser beam. In general, bright surfaces reflect a bigger portion of the emitted light than dark surfaces. This reflectivity value is used to assign a corresponding grey value to each single point.
The single point measurements are repeated 976,000 times per second. The result is a so-called "Point Cloud", a 3-dimensional grey scale photograph of the scanner's enviremont. Depending on the selected resolution, each point cloud consists of millions of scan points.
In short, the scanner takes a 360 degree image of an area and renders it in three dimensional space. It provides a "virtual reality" with unrivaled accuracy from which designers and engineers can base their work.
High resolution 3D scanning is a well proven and accepted technology in the plant design industry today, offering the designer a unique opportunity to have a detailed and accurate "as-built" 3D dimensional knowledge of the entire area before the design phase is started. In the past, the designer relied on out-dated drawings and information that was possibly inaccurate, as well as a limited number of field measurements which we obtained with a standard metal tape.
The above is a HPU modeled to check interferences between the new bottle racks being placed in the room and the existing equipment in the room.
The above is the point cloud used to generate the 3D model to the left. The room was scanned with the laser scanner then those points used for the model, allowing for extreme accuracy.