This was done via the new spherical projection script in Anime Studio, but the same feature exists in most 3D programs. I always wanted to use this for painted backgrounds, but never found some useful grid for it. So I did one myself, here it is for everyone to use:
![Image](http://slowtiger.de/examples/panorama_grid_2.png)
The image used for the example above:
![Image](http://slowtiger.de/examples/zimmer4kl.jpg)
The bookshelf in the back is something I did quite a while ago and re-used it already in different projects. Import the image into TVPaint and use the warp grid with some good resolution, I used 7 horizontal and 6 vertical points. Select columns of points first (marquee select) to shift horizontally in place. Then place the points so the connecting lines meet or follow the grid lines.
Maybe I'm a bit obsessed with the clear lines, a more painterly approach could be better. Looking forward what others do with this!