So I tried to find the source for this and I ended up on a video titled "Windows 10 Hero Desktop Image - Behind the Scenes" on the channel "Signum Game Studio." This looked very promising but I couldn't watch it because youtube kept crashing about 2 seconds into the video. This has never happened before and it seems to only be this ONE video.
If anyone else can find an try it, let me know if it works for you.
I found what I think is a reupload of it though, and it does seem they did this with actual cameras and lights, which is pretty cool.
It can be found on phoneArena in the July 01,2015 posting entitled "Download the stock Windows 10 wallpapers for your tablet or convertible here". First line in the article is "Taking a page from the Apple Watch face efforts, Microsoft used lasers, projectors and camera-mapping to create the new misty logo that you will be seeing in the default Windows 10 wallpaper on your tablet, computer or convertible with the latest OS from Redmond." Highlight quoted text and web search should get you there.(this site won't allow me to post direct links) Cheers.
If anyone else can find an try it, let me know if it works for you.
I found what I think is a reupload of it though, and it does seem they did this with actual cameras and lights, which is pretty cool.