3D scanning is the process of collecting data on the surface of an object and creating a 3D representation of it. High-end professional scanners work by beaming lasers onto the surface of an object and measuring the distance of each reflected point. This data is then collated into what’s known as a ‘point cloud’. 3D scanning software then processes, or reconstructs, the point cloud into 3D geometry that can be read by 3D design software, and then later by 3D printers. This geometry is often referred to as a ‘mesh’ and can be thought of like a net. When processed, each point in the point cloud connects to form vertices, similar to the squares in a net.
123D Catch works in a slightly different way, by analyzing a collection of 20-40 images of the object you want to scan, with each image taken from a different angle around the subject. From those images, 123D Catch automatically assembles a 3D mesh of your object, with much better results than you might expect. It’s a simple, easy to use ‘one app does it all’ piece of free software that gives great results fast.
Scanning objects with 123D Catch.
123D Catch is a FREE application from the makers of the world’s most sophisticated 3D software, Autodesk. Responsible for creating high end visual effects, industrial design and architecture software, Autodesk have utilized what they have learned to offer this simple to use, free 3D capture app. It’s available as a web-based application, an app for the iPad and iPhone, and as an application for desktop Windows users. You can download it for free at 123dapp.com/catch.
Taking pictures for scanning.
Before you begin snapping away with your camera and start scanning, think a little about how you’re going to photograph your object. The quality of your final scan will be a direct result of the quality of the images you provide Catch to process. Taking a little time to think about how you will set up and shoot your object will greatly improve scanning results.
Try to find a place with lots of light.
The more light you can have on your object the better. Darkly lit objects will be much harder to scan, with less information being supplied for Catch to process. Also consider the coverage of light. Having lots of light on the front of your object and very little behind may give you some ‘interesting’ results. The more evenly lit your object is, the ‘cleaner’ your scan will look.
Get good photo coverage.
Make sure you’re not making the task too difficult for Catch by taking the time to photograph your object properly. Between each photo you only want to move around the object about 5-10 degrees and keep at least 50 percent of the area covered in the previous photo within the frame. Think of it as if you’re taking multiple pictures that will be used for assembly of one 3D panoramic photo. If each one overlaps the previous, it makes it easier to ‘stitch’ them together. The same is true for 123D Catch, although with 3D there is depth to calculate as well as surface, so the more information you provide (smaller angles between photos), the better your scan will be.
Use background ‘markers’.
At first it may seem like placing your object on a plain white or black background would be better for scanning, when in fact the opposite is true. 123D Catch uses background objects as well as the object you want to scan to enable it to more effectively calculate the depth of your photos. If possible, use some high contrast tape to place markers in the background of your pictures. You should aim to have at least 4 markers within any picture you take.
Give yourself room to move.
Once you start taking pictures you will need to easily move around to keep your images smooth and consistent. Make sure the area around both you and the object is clear of obstacles and that you have room to move around. Once you get started, it’s best to take all your photos in one smooth sequence, so having a clear ‘run’ will help you focus on what you’re photographing, not where you’re stepping.
Things to avoid.
While 123D Catch can do some amazing things for scanning, there are some limitations. Objects that have transparency will not scan very well or even at all. The surface can be either a hole or a warped exterior, as too could be any reflective surfaces. And so, at least for the time being, scanning transparent objects should generally be avoided.
If you would like to learn more, you can watch Autodesk’s 123D Catch tutorials at 123dapp.com/catch.