What technology is used to build multitouch applications?

Can anyone provide any details, code snippets, examples, etc. of how to go about building something as cool as this "Rock Wall" that Obscura Digital built?

http://www.obscuradigital.com/work/detail/rock-wall/

Let's just pretend we have access to whatever technology is required. 开发者_StackOverflow社区Where do I start?

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http://www.microsoft.com/surface/en/us/default.aspx

http://weblogs.asp.net/scottgu/archive/2007/05/30/microsoft-surface-and-wpf.aspx

http://multitouchvista.codeplex.com/

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My understanding of the question is, what kind of libraries are available for multitouch (specifically in .Net)?

If this is the case, see here and here. Neither actually requires a Microsoft Surface table, but it does require multi-touch compatible hardware and Windows 7.

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http://www.perceptivepixel.com/ founded by Jeff Han

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Have a look here:

TouchKit: the open source, multi-touch screen developer's kit
http://www.gizmag.com/touchkit-the-open-source-multi-touch-screen-developers-kit/9852/

You need a large piece of plexiglass, an infrared webcam, a projector, several infrared LED's, and some sort of translucent material like butcher paper.

The infrared LED's are placed along the outer edge of the glass, and illuminate the glass with infrared light. The projector takes the computer image and projects it onto the butcher paper, which is mounted behind the glass. When you touch the glass with your finger, it produces an image in the infrared camera that can be processed by the computer.

The whole thing can be built for less than $1000. TouchKit offers everything but the projector in a pre-assembled form for $1580, including shipping.