Are the red strings used by Dexter a real thing?

Question

Dexter works as a blood splatter analyst for Miami Metro police. We often see him on a crime scene using red strings to represent the trajectory of the blood:

Is this a real thing done by blood splatter analysts or is it made up to make Dexter's job more "fancy" ?

Answer 1

It's a real method for analyzing blood splatters.

To find the area of convergence, investigators typically use string to create straight lines through the long axis of individual drops, following the angle of impact along a flat plane, for instance the floor or wall where the drops are found. Following the lines to where they intersect shows investigators where the victim was located when the drops were created.

To find the area of origin, investigators use a similar method but also include the height calculations. This creates a 3-D estimate of the victim s location when the drops occurred. For example, if the area of origin is determined to be only two feet above the area of convergence on the floor, the analyst may presume the victim was either lying or sitting on the floor. If it is five feet above the convergence, the victim may have been standing. This analysis can be done using strings and a protractor, mathematical calculations or computer models.

( Source: forensicsciencesimplified.org)

Refer Wikipedia for knowing more about string method.