We’ve now laser scanned a Pendolino power car at the Virgin Talent Academy at Crewe. The weather was cold, dull and overcast – but not rainy – apparently ideal scanning conditions! If it’s too bright, or the surface is wet and shiny – reflections can make it a lot harder for the laser to get a clean fix.
The laser scanner is made by Leica and costs around £70,000. It’s known as a “time of flight” scanner – that is, it measures the time it takes the light to travel out and be reflected back, and from that calculates the precise distance to the point. It generates a million data points per second, and at the range the scan was carried out is accurate to +/- 0.3mm. When this is scaled down for N gauge the error margin is around 2 micrometers!
The whole process took around 3 hours and involved the two operators – David and Jonathan McCrory of Scantech International – postitioning the scanner at various points and allowing the laser to make a sweep. They first scanned around the train at low level, to ensure bogie and underframe detail was captured, before using a tripod and the platforms present to scan further up and eventually along the roof to ensure the entire body was scanned.
The resulting “point clouds” from each pass will be stitched together, cleaned up and extraneous items such as the track and any fencing/shrubbery removed to give Rapido’s CAD designers a clean outline to begin designing the model. Look out for more updates soon!