Week 43: 3D Scanning and Photogrammetry

Another week, another tool introduced to us. Through the duration of this week we have been focused on the application of 3D scanning, specifically on a facial structure.

3D Scanning

Using 3D Coat, I was able to utilise a photo from 123D Catch and apply a mesh manually using said 3D reconstruction as reference. It is a fairly straight forward process. Using 123D Catch, you insert photos of whatever object you have chosen (a face in this case) in a way that allows the software to render a complete 360 degree model. This model is then imported to 3D Coat where is can be altered and manipulated in a great number of ways. From painting and texturing to retopology and sculpting.

For practice we were tasked with working on faces of our own (I originally meant to use my own face for this, but I was unable to make a fully realised turnaround model due to a lack of photos). The results were… decent for a first try I suppose. I redid it a handful of times just to get the overall layout in a somewhat consistent manner. It always became a mess with inconsistent lines and unconnected polygons. It took three attempts before I managed to make a continuous line work with the connecting star on the cheek and underneath the nose in accordance with Angela Guenette’s system.

I eventually got the hang of it, learning to perceive the eyes, mouth and nose to be separate parts connected by the rest of the polygons. While these were helpful guidelines I needed to be careful with relying too much on other references. Every face is different and unique in some way, and I would have to study my own model closely in order to understand how the lines would be placed accordingly.

Photogrammetry

(http://www.theastronauts.com/2014/03/visual-revolution-vanishing-ethan-carter/)

Reading into the use of Photogrammetry during the development of “The Vanishing of Ethan Carter” I could instantly see the benefits of this technology if executed properly. It allows for fully realised objects that only require miniscule manipulation after implementation at most.

It is however not as simple as it sounds, as pointed out in the article. While an excellent way to capture your items in a way as close to the real thing with unique textures as possible you have to not only make sure every possible angle is covered with your camera, you must also reconsider everything you know about lighting. Highlights and contrast are the complete opposite of beneficial in this context as it will disrupt the information captured by the camera and make it inconsistent for the scanning process. In short, it requires you to rethink everything you were taught about photography. You need slightly dulled lighting when the sun is blocked by the clouds in order to have a neutral portrayal which the scanning software can read correctly. You also need to take photos from as many angles as possible, otherwise it won’t be able to be fully reconstructed. As was the case with my own face, as it didn’t have enough photographed angles to utilise.

That wraps it up. Until next time!

Björn Erik Berndtsson. Graphics and Game Design.