DAVID-Shapefusion is described as 'allows a convenient alignment and combination of 3D scans from different viewing directions'. There are five alternatives to DAVID-Shapefusion for Windows, Linux and Mac. The best alternative is ReconstructMe. It's not free, so if you're looking for a free alternative, you could try 3D Underworld or SLStudio. Other great apps like DAVID-Shapefusion are FlexScan3D (Paid) and DAVID-laserscanner (Free).
Structured light scanner is a tool to reconstruct point cloud from series of images lit by patterned light. As showing in the following image, patterns are projected to the object in the grid manner. Each cell in the grid has a unique sequence.
DAVID is a software for 3D laser scanning. All you need to build a 3D scanner is a PC, a camera (e.g. a webcam), a background corner, and a laser which projects a line onto the object you want to scan.