Turn Photos Into 3D Models With Autodesk 123D Catch [Currently Only Windows]

转自 http://www.makeuseof.com/tag/turn-photos-3d-models-autodesk-123d-catch-windows/

With the 3D printing revolution officially under way, the problem remains of how to get actually get a digitized 3D representation of something. You could start from scratch, using something likeGoogle Sketchup, but I’d be lying if I told you it’s easy to create anything reasonably complex. Instead, it would be great if you could just take some pictures of a real life object, then somehow auto-magically transform that into a 3D model.

Magic – meet reality – in the form ofAutodesk 123D Catch

Introduction

123D Catch is just one of a range of free software from the CAD and modelling powerhouse Autodesk, and though I may take a look at the other apps at a later date, today we will be looking specifically at just 123D Catch.

The app takes a selection of photos of an object – the more the better – finds identical points and dinstinguishing features between them, and merges them all together to create a fairly accurate, realistically textured, manipulable 3D object.

Getting Started

To download, you’ll need to create a free account at Autodesk. The social network buttons make this easy though. Right now, the app is Windows only, but iPad and web versions are on the way.

To learn the process, it’s best to use the sample project that comes with 123D Catch. Open the app, select New Photo Scene, and select all the photos in theProgram Files/Autodesk/123D Catch/sample_project/ directory.

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Click Compute Scene to start the magic. The first time, a popup will ask for your name and email; the newsletter is optional though. Your images are then uploaded to remote services in the cloud (ignore the bit that says “Photofly” – this was the old service that Autodesk bought and renamed, and customizing that was overlooked). You can choose to have the service email you when your render is complete, or just sit and wait. About 20 minutes to an hour is realistic.

Note: I experienced disk access issues on Windows 7. Running the app ‘as administrator’ solved this.

When complete, your 3D scene will be built and opened in a basic 3D editor.

Navigating & Editing

To move around and check out the scene and model, use the group of 4 blue icons. Your mouse wheel can be used at any time to zoom and pan, but for rotation you’ll need to use the 3rd icon in this group.

To crudely cut bits of the model out, use the basic selection tools and right click -> delete. This app isn’t designed to be a full 3D editor of course; these tools should only be used to cut out bits of the background in the scene. For finer control, exporting the 3D model to a full modelling application is needed.

Tips For Good Models & Limitations

On your first attempt, you may end up with a blurry mess or nothingness; or you may just get a render error. To avoid this, there’s a few things you can do:

• Use a fixed exposure and focal length – camera-phones will often auto-adjust exposures for each shot. Taking pictures on an overcast day or somewhere with fixed light (in a studio, for example), will help; or simply use the exposure and focus lock on your camera. To do this on the iPhone, hold down on a focus point – you should see the text AF/AE lock now appear at the bottom of the screen (this, and more iPhone tips in our free, downloadable iOS5 guide).
• Don’t perform any editing on the photos themselves – no cropping – just keep the camera in a fixed orientation, and give the app good quality, consistent shots.
• To help stitch photos together, add additional reference points – color squares to a blank wall for example –  or anything to increase the complexity of the scene. If everything looks the same, it will be impossible to figure out which points match.
• Transparent, reflective or overly glossy objects won’t capture.
• If you’re capturing humans or live animals, make sure they absolutely don’t move an inch!
• Check if manual stitching is needed by scrolling through the photo browser at the bottom of the main screen. If you see any that are greyed out with a yellow warning sign on them, you can attempt to manually stitch them into the scene. Rather than explaining this in text, this tutorial from Autodesk explains the process rather well I think.