Panoramas in Second Life
A Panorama of The Tech in Second Life
This picture shows you everything you could see by standing in front of The Tech in Second Life and turning in a complete circle. The Tech is in front of you and things behind you appear at the sides of the picture.
A Normal Snapshot
This snapshot was taken from the same spot as the panorama above. Notice that you can only see a small portion of what was visible in our panoramic picture.
To make the panorama it was necessary to combine 12 different snapshots taken from the same spot. Two sets of six overlapping snapshots were taken. Each set of six covers the entire horizontal view.
Snapshots for a Panorama
These are the snapshots we used to make the panorama. Notice that the pictures overlap. Some things near the edge of one picture also appear in the next.
Also notice that we can't just overlap the pictures. Adjacent images don't quite fit properly. We need to do something more.
We need to reproject the images. One way to think of reprojection is to imagine printing our snapshots on a rubber sheet that we can stretch into another shape.
Seeing How the Pieces Fit
This is how reprojection changes our original snaphot, and the snapshot just to the left of it. Notice that after we stretch the image into a different shape by reprojecting it, the two images fit together quite nicely.
The panorama software used identifiable locations called control points in the overlapping part of the pictures to determine how to reproject each image. For these images, the corners of the white square window, and the edges of the door to The Tech Museum Shop were used as control points.
Putting All the Pieces Together
We can now see how all of our reprojected snapshots fit together to form our panorama. The white lines shown here do not appear in the final panorama, they were added so you could see how the individual images fit together. If we crop the picture into a rectangle suitable for framing, we have the final panorama shown at the top of the page.
A Polar Reprojection
But the fun isn't over! We can take our panorama of The Tech Virtual and reproject it once again.
Because the panorama covers 360 degrees horizontally, the far left side of the picture, and the far right side of the picture are actually the same place. So if we join the two side edges they will match.
Here we've done that with a polar stereographic projection that puts the entire bottom edge of the picture in a single point in the center of a circle, and puts the top edge on the outside edge of the circle. The left and right sides meet at the bottom of the circle.
You can learn more about polar reprojections, including how to make your own.