How Laser Scanning for 3D Printing Actually Works

About twenty years ago, personal computers gained the necessary memory and processing speed to perform all the complex calculations necessary to plot the locations of high-resolution three-dimensional objects in space.

The most conspicuous demonstration of this technology came in the form of video games which became capable of animating scenes and three dimensional characters from the player’s viewpoint. Once the math problem was solved, it didn’t take long for the calculations to find their way into hardware and then into the real world.

Twenty years later, the solutions to those math problems gave rise to a new technology called a 3D Laser Scanner.

What Does a 3D Scanner Do?

In order to derive the shape, size and location of an object in space, a scanner plots the locations of many points on the surface of the object and determines their distances and angles based on a fixed point. Once all of the points on the surface of an object are plotted, specialized software creates a list of coordinate values called a “point cloud.”

The point cloud can then be used by other specialized software to reconstruct an object in virtual space, or can be used by a 3D printer to reconstruct the object in real space.

How Does it Work?

Trigonometry is a key mathematical concept in a 3D technology called “Triangulation Scanning.” Trigonometry is the study of the mathematical properties of triangles. It holds that if you know the length of one side of a right triangle, and at least one of the angles adjacent to that side, it is possible to derive the lengths of the other two sides due to their inherent fixed relationships.

With a 3D LASER scanner, the triangular shape is defined by three points. The first is the fixed point from which the LASER emitter is fired. The second is the location where the LASER collides with the object being scanned. The third is a camera that is held at a fixed distance and angle from the emitter’s original fixed point. The angle formed by the line from the fixed point to the object and the line from the fixed point to the camera is always a right angle.

All that is necessary to determine exactly where in space the LASER collides with the object is to know the angle formed by the line from the camera to the point where that collision takes place.

Three dimensional printing and scanning are technologies likely to lead the world into a third industrial age. New processes like micro-manufacturing, on-demand merchandising and all manner of other do-it-yourself building capabilities will help fuel the industries of the future.