Toyota recently wanted to know if a new car could be built using the equipment it already had in place. A little investigation turned up almost no information on the production machine's dimensions. The company's first attempt to build a model from drawings proved unproductive, frustrating, and time consuming. It was also impractical to tapemeasure factory-floor equipment because the line had to be shut down first. And tape measurements were inaccurate.
In contrast, laser-scan accuracies are ±3 mm. It takes 2 to 3 hr to scan a large production machine and as much as 40 more hours to turn point-cloud data into CAD models. "Each scan generates about a 250-Mbyte uncompressed file, and we complete six or seven scans on one piece of larger equipment," says President Les Orford of Can-Tech Design Inc., in Canada.
After a scan, Orford's team uses specialized software that handles large data sets to process point-cloud data into solid models with high detail. "There is no magic button to speed the conversion. It has to be done by hand," Orford says. "Toyota identifies the important areas and we concentrate on them."
The software used to convert point cloud to CAD is Light Form Modeler (LFM) from Z+F UK Ltd. It creates solid models from point-cloud data, but needs inputs from the operator for details such as pivot points, joints, cylinders, and productcontact areas. Can-Tech creates each part as an individual element so it can be modified when needed. Machine parts that contact the car body need highest detail. Laser scanning also comes in handy because "a lot of machine builders don't supply 3D CAD geometry with their equipment.
They might deliver 2D drawings but there isn't enough information in them to build 3D models. In fact, they often contain only the overall dimensions or anchor holes," says Orford. And when CAD models are supplied, they often don't reflect the " asdelivered" equipment.
Can-Tech Design Inc., can-tech.com