TOM'S DIGITIZING PRIMER
Graphic: Skiron on MS bridging slide diagonal LL to UR with scan across part in top triangle and probe touching same part in lower triangle.
Data collection can be broadly divided into contact and non-contact methods and data density.
How you choose between one method and another depends on many factors related to approach limitations, complexity, time, and budget.
Contact - immediate mode results, usually less expensive. Prismatic parts. Highest accuracy.
Scanning - results after post processing, collect data now, work on it later, often more expensive hardware and software. Highly detailed, organic parts. malleable parts.