Have you ever wished that you could easily transfer a real object into a digital file? The technology is here, but most of us simply do not have access to high-end 3D scanners that can reconstruct the digital geometry of a physical model. Not to mention that some objects can be way too big for any traditional 3D scanner. However, there is another, much cheaper way to create 3D models corresponding to real-world objects.
What is photogrammetry?
Photogrammetry (or SFM – Structure From Motion) is a process that estimates the three-dimensional coordinates of surface points using pictures of a single physical object taken from different angles. At least that’s the oversimplified one-line explanation. You take a bunch of pictures of the object from all possible directions, then you use these photos as an input for a specialized software. This software will look for features that are visible in multiple pictures and try to guess from which point was the picture taken. Knowing the camera positions and orientations, it creates a 3D point that corresponds to the 2D feature on the photo (basically a pixel). Ideally, you’d get a finished 3D mesh as an output. But often it might be better to process the reconstructed points into a mesh manually for much better results.
The list of available photogrammetry software is pretty long. The problem is that most of the programs are either very expensive or limited in features in the free version. Some programs even offer cloud-based computation, which is handy, but further increases the cost.