Photogrammetry: what is it and how is it used in 3D printing?

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Photogrammetry is a technique for obtaining reliable data from real-world objects in their natural state by creating 3D models from photographs. 2D and 3D data are extracted from an image and, through superimposed photos of the object, building or terrain, are converted into a 3D digital model. This makes it possible to capture large objects, even landscapes, which would otherwise be impossible to scan. Photogrammetry is therefore often used by surveyors, architects and engineers to create topographic maps, networks or point clouds.

The role of photogrammetry is very important, especially in topography. The advantages of photogrammetry over traditional surveying tools are numerous. For example, photogrammetry is both faster and more agile when it comes to data collection. It is also possible to obtain renderings of terrain that is difficult to access, especially nowadays, where the use of drones in photogrammetry makes it possible to reach all kinds of places. All the details of the terrain can be mapped continuously through the photographs obtained.

photogrammetry

One of the uses of photogrammetry is in the world of archeology (photo credits: PAR – Archeologie et Patrimoine National)

Using photogrammetry in 3D printing

As we mentioned at the beginning, photogrammetry is the technology that allows us to create 3D models of real objects from photographs. The process is as follows: a series of photographs are taken around the object and then, using specific software, these are converted into a 3D model. By taking photographs (or videos) of the object from different perspectives and under constant lighting, the specialized software is able to find representative or characteristic points of the model that are repeated in all the photos. Also, with a few photographs, we can create the so-called stereoscopic effect that is needed to infer the height of any object on the earth’s surface based on the shadows cast by each object, allowing us to increase accuracy of the scan.

Using keypoint extraction techniques, the software is able to infer the distance of points through the separation between them in different photos, creating a cloud of feature points. Finally, this point cloud is converted into a mesh, which can be processed or cleaned for 3D printing.

Photogrammetry

Photogrammetry carried out with drones (photo credits: Geomatic)

These days, there are many possible applications for any 3D scanning technique, but photogrammetry is particularly useful because it doesn’t require specialized tools and anyone can do it with just a cell phone and a computer. However, what is usually needed is powerful hardware: most photogrammetry programs require a computer with sufficient capacity to process the images and generate the 3D scanned model.

Some of the common uses of photogrammetry are the digitization of sculptures: first the desired model is digitized with photogrammetry and later, with 3D printing, we proceed to obtain a miniature or large scale model of this one. Another use of photogrammetry is the digitization of industrial parts: we often want to repair equipment or an element of which we are missing a part or which has broken. This is very common in the automotive market, where often stratospheric prices are charged for certain structural or body parts due to their limited availability. Thanks to photogrammetry, we can scan an original piece with high market value and proceed to reproduce it by 3D printing, obtaining an exact copy of the original for a much lower price.

The different software

Nowadays, there are different types of photogrammetry software. Of course, there are commercial solutions ideal for industrial and engineering applications. But there are also a large number of free downloadable programs where you will only need a camera or a phone to take pictures and, if you have access to a 3D printer, you can even print your models by the following.

If you want to learn more, be sure to check out our compiled list of the best photogrammetry programs available, selected and sorted alphabetically. Here we showcased the best photogrammetry programs available: from free programs like Blender to paid professional software for creating more accurate 3D models, like ZBrush.

Image of a castle using the OpenMVG photogrammetry program (photo credits: Open MVG)

What do you think of photogrammetry? Would you use it for your 3D printing projects? Let us know in a comment below or on our Linkedin, Facebook, and Twitter pages! Don’t forget to sign up for our free weekly newsletter here, the latest 3D printing news straight to your inbox! You can also find all our videos on our YouTube channel.

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