Updated: Aug 19
Applying a marker or markerless motion capture system can be dependent on your needs.
Both motion capture systems have their strengths and weaknesses. To start, lets review marker based technologies. Their strength is found in the adaptability of the marker model. For example, you can add 30 markers to track a variety of issues related to the foot. This hyper focused models is great when tracking objects. The weakness in marker based systems is setup time, artifact from skin movement, and the human error added when tracking humans. Markers tend to move or fall off and the repeatability is not that great.
Next, lets review markerless motion capture (spefifically DARI). Their strength is found in repeatability of tracking humans at scale. With no human error added, each person will have the same tracking error regardless of the system. Plus, with no markers you have virtually zero set up time and you can scale (volumize) your capturing opportunity. The weakness in markerless based systems is the lack of adaptability for things other than humans. What makes for great scale also creates little ability to accommodate any model changes.
Quick conclusions. If you are tracking full body human movement use markerless motion capture. If you want to track a unique object use a marker motion capture system.