3D scan two different objects each using a different technique:
For one object, use a market/commercial 3D scanner device, such as:
For the second, use one of techniques discussed in class (such as SLAM ARCore on Android/3D scanning on iOS/OpenKinect/ReconstructMe/Structured Light scanning/Photogrammetry softwares or another app in your phone).
SLAM:
Simultaneous Localization And Mapping (SLAM)
SLAM stands for Simultaneous localization and mapping. It is the computational problem of constructing or updating a map of an unknown environment while simultaneously keeping track of an agent's location within it. SLAM algorithms are based on concepts in computational geometry and computer vision, and used in robot navigation, robotic mapping and odometry for VR and AR.
Basics of AR: SLAM - Simultaneous Localization and Mapping - andreasjakl.com
Summary: As the basic of AR technology, SLAM algorithms enable your AR device to understand and map out an unknown environment while real-time tracking camera position, different features in this environment, including their locations and relations. This algorithm capture environment features by frames in which keypoints are detected and converted to 3D coordinates(map points). By comparing a new frame with some old frames, the algorithm then gets to make corrections in the map and update its knowledge about this environment. Since the data we feed the algorithm is from sensors like GPS, accelerometer, and gyroscope, inaccuracies in the algorithm's output cannot be removed, though the reliability and the speed have both been improved magnificently in recent years.