The AR Sandbox typically has a 4:3 aspect ratio because that’s the native aspect ratio of the Kinect camera, and used to be the typical aspect ratio of digital projectors.

The latter is no longer the case, with 4:3 projectors having gone extinct. The project site still recommends using a native 4:3 projector, but I will change that as time permits.

So here are some general notes about projectors and how to use them for the AR Sandbox.

1. Using a wide-ratio projector such as 1280×720, 1280×768, 1280×800, 1920×1080, etc. etc. is perfectly fine. Such projectors should be set up to fill the AR Sandbox on the short (back-to-front) axis, and will then over-project over the left and right edges. But the SARndbox application will naturally project black in those areas, meaning the over-projection will be hardly visible and will not matter.

2. Never run a projector at non-native resolution, or with digital keystone correction enabled. Both will involve the projector re-sampling a digital image at one resolution into a digital image at another resolution, which will always create ugly artifacts, especially in features like contour lines. Neither of these are necessary. The AR Sandbox software is capable of running at whatever resolution and aspect ratio is native to the projector. Look for keystone correction in the projector’s menu, and set both horizontal and vertical correction to “0” (or whatever means “off”), and look for and disable any potential automatic keystone correction. In the AR Sandbox, keystone correction is handled by projector calibration, and it does a much better job at it than any projector ever could on its own.

3. Only use optical corrections, i.e., optical zoom, optical focus control, or optical keystone correction (some very expensive projectors have it).