3D Week 8 – 3D scan, Retopo and Photogrammetry

During our eighth week in the 3D1 course we learned about modelling faces. One of the weeks’ exercises was to make a retopo of a 3D scanned head, meaning that we were to clean up the topography of the model, making it simpler whilst still maintaining the same shape. Those of us who wanted to got to try and make facial scans of our own heads to work with. In order to make a 3D scanned object you need to take pictures of it from several angles, preferably as many angles as possible. The more photos you have of the object you want to scan, the more information the program will have to match the images together, and the more information the program has the better the scan will become. Sometimes the program won’t be able to read all of the photos correctly, and you might need to go in and manually move photos and correct the model to get it right.

When we had the photos we were to add them to a program called “123D catch”, which would let us create a model from the photos. I had trouble signing in to the program however, as I couldn’t remember my password, so I wasn’t able to create a model from my own face, and instead went with a finished scan of another head so that I could follow in the exercise.

When the 3D-scan was finished, or we had gotten our hands on the already finished scan, we were to use our trial version of “3D coat” to build a model on top of the scan. We were to mainly focus on modelling around the eyes and mouth, those areas being some of the most important edge flows in the face, especially if you want to be able to animate the face later on.

Another thing we were asked to do this week was to read this article on “Photogrammetry” in the game “The Vanishing of Ethan Carter”. I’d already watched some footage of the game, and found the game world beautiful beyond any other game world that I’ve looked at up to date, and reading through the article I understood why that was. Creating believable, living environments is a very hard thing to do, and none does it better than nature itself. An artist can think that he knows how wear and tear on objects should look, but not even the best artists can compete with the real thing, and using photogrammetry this game added just that believable-ness that many other games tend to lack. I can’t say that I’m anything but utterly impressed by how they’ve created the environment of this game. Photogrammetry is basically the same technique as what we used to scan our faces – taking a multitude of photos of an object in order to create a 3D scan of it, but used in a much larger scale in order to recreate environments, from rocks to entire hillsides.

The technique isn’t perfect however, and it’s very time-consuming. There are many factors to consider when taking the photos, such as how sunny it was, the light and contrast, and making sure that none of the images where shaky. The article linked above describes the process in detail, and I’d warmly recommend reading it.

Cheers!

/MPh