Jerlena Rittwage’s Hand Project
Rapid3D was approached by Colin Pischke from Print Your Mind 3D to assist with a unique and challenging project – Jerlena Rittwage was born with an underdeveloped hand. Colin and his team at Print Your Mind 3D wanted to create a custom prosthetic for Jerlena, since traditional prosthetics do not fit her uniquely shaped wrist and hand.
A previous method employed to capture the shape of Jerlena’s limb involved the use of cast silicone. There were difficulties casting far enough past the elbow joint as well as maintaining the shape of the silicone cavity after removal of the limb.
Rapid3D chose the Go!SCAN Spark for this application. This is the newest portable white-light scanner from Creaform. It scans 1.5 million points per second at a local accuracy of 0.050 mm. The scanner can use a feature called “Semi-Rigid” positioning, which is useful for, and perfectly describes, scanning a human being. People can sit still for a short period of time, but are never perfectly rigid due to breathing, twitching, gravity, etc. This feature is helpful because the Go!SCAN allows the position of the targets or features to be more lenient since the scanner is expecting the object to wiggle or move slightly.
We wanted to make sure that Jerlena’s arm was in a comfortable enough position that she could hold still for a while, but we needed to make sure we could scan all the way around her arm and hand. We attached some adhesive 6mm targets to her forearm and propped her upper arm in a pipe stand. This provided the support Jerlena needed to keep still while giving us access around her arm with sufficient positioning targets to keep the scanner tracking properly. Targets allow for more dependable positioning of her thin forearm.
Scanning resolution was set to 1mm and we got great data on the first try. Jerlena sat incredibly still and the field-of-view of the Go!SCAN certainly helped – a 390mm x 390mm scanning area captures a lot of data, and quickly. We got coverage up to her shoulder on the inside of her arm, and up to where her tricep was resting on the pipe stand on the bottom.
Using the Creaform VXmodel plug-in for VXelements, excess data was trimmed and the scan made watertight. A quick alignment to a coordinate system was performed and an autosurface created for Colin and Print Your Mind 3D to help design a custom hand for Jerlena.
Check out the video below to see how quickly the scan was completed.