At Catesby Projects, one of our main uses of our 3D scanners is to scan athletes. We scan athletes for a variety of sports and for a multitude of reasons. Some of these athlete scan models become 3D printed mannequins, primarily cyclists in a time trial for the purpose of repetitive wind tunnel testing. Our sister company, Vorteq Sports, regularly use mannequins of this nature for aerodynamic testing with their customers at Silverstone Sports Engineering Hub.
For athlete scans we use the Artec Leo 3D scanner. This particular scanner is a handheld, cordless device that allows us to freely scan the subject with real time 3D image generation. This scanner works by using a structured laser light projector and two cameras. The structured laser light projector emits a grid of laser lines on a surface, of known spacing, which changes and distorts over an objects surface. The result of the scanning process is a 3D point cloud which is then processed to develop a useable 3D model.
“3D Printed mannequins help increase robustness and repeatability of your cycling performance testing.”
The scan files that are generated by the 3D scanner are first imported into the Artec studio software. In this software, the generated point clouds are globally registered (a process that aligns multiple scanned point clouds into a common coordinate system) and then turned into a mesh of triangles.
Through a process called smooth fusion, these meshes are then turned into smooth and seamless models. These meshes are then turned into smooth and seamless models through a process called smooth fusion which analyses overlapping regions to blend data together and remove any artefacts or floating mesh triangles.
The smooth meshes are then exported as STL files to another processing software which allows us to fill any gaps or holes in the mesh as well as align them to other scans, a specific position or an object.
The smooth, complete and watertight 3D athlete models are divided into sections to fit the print capacity of our 3D printers and to allow simultaneous printing of parts. Mannequins are usually divided into four arm pieces, four leg pieces, six torso pieces, two feet, two hands and a head. Specific joint geometries are added to aid with assembly.
We print the processed scan pieces on our fleet of twelve Fused Deposition Modelling (FDM) 3D printers. FDM is a 3D printing method that creates objects by extruding melted thermoplastic filament layer by layer. Our printers have a 300mm x 300mm print bed size with a maximum vertical print height of 600mm, which allows us to comfortably print long limbs and wide torso pieces. Before printing, each body piece is divided into layers of specific thickness for the correct layer height of our printers. This also gives us the opportunity to reduce the infill percentage of a print. Changing the infill of a print means replacing solid internal areas of a part with geometric patterns to reduce the amount of material used in a print. For our prints we use a honeycomb infill pattern which maintains strength but reduces the mass.
Once each part is printed, the pieces are either bonded or bolted together. Arms, hands, legs, feet and head are fitted with magnets to make them detachable for quick assembly. These mannequins are utilised regularly by our sister company, Vorteq Sports, for testing in SSEH’s human performance wind tunnel. The main advantage to using a mannequin over a real athlete is it remains in a fixed position throughout a day’s testing. The stability increases robustness and repeatability of testing, allowing smaller changes to be detected due to the fact that any variation in position is removed. For a professional cycling team or equipment manufacturer a mannequin also removes the need to source an athlete, who’s race and training schedules are often extremely busy.