Microsoft today announced a technical preview of its third-generation technology for creating 3D-like environments via photo stitching. The first two generations of Photosynth technology, called original synths and stitched panoramas, are still available on the main site, but from what we’ve seen, the new preview is much more advanced.

For those who don’t know, Photosynth lets users capture the places they love in high resolution and full 3D. If you sign up, Microsoft says it will enable accounts for these new synths on a first-come first-served basis.

The new Photosynth technology supports four basic experiences: spin, panorama, walk, and wall. Spin lets you pivot around an object regardless of its size, panorama puts you in the center of a space and lets you look in every direction, walk follows a path toward any direction, and wall lets you slide across a scene.

Here’s an example synth that lets you play with all four:

The above was created by Glacierworks.org founder David Brashears, a mountaineer and photographer who captured the approach to Mt. Everest during one of the highest elevation helicopter flights ever attempted. Microsoft partnered with him to show off its new Photosynth tool.

“This is the experience I was dreaming about when I decided to capture the environment of Mt Everest from a helicopter flying at extremely high altitudes,” Brashears said of his synth. “It brings a completely new perspective to the mountain. I’ve never seen anything as smooth and glorious as the new Photosynth of my Everest flight. It’s like a video, but you can stop on any frame and zoom in.”

The Photosynth technology works by first looking for points (called “features”) in successive uploaded photos that appear to be the same object. The next step is bundle adjustment, a standard technique in photogrammetry that determines where in 3D space each feature is, exactly where each photo was taken from, and how the camera was oriented for each photo.

The technology then uses the feature points in each photo to generate 3D shapes, on a per-photo basis rather than trying to generate a global 3D model for the scene. It then calculates a smooth path through the locations of the camera for each photo, in order to present the experience of moving through a synth as a gliding motion (even if the actual photos were shot at different heights or slightly off-angle).

Lastly, Microsoft says Photosynth slices and dices the images “into multi-resolution pyramids for efficient access.” Once a synth is created, you can now easily share it to Facebook, Twitter, or via embed (as you can see above) with just a few clicks.

Top Image Credit: BT