From a post in Slate:
"For his dazzling “Woodswimmer” video above, filmmaker Brett Foxwell, who goes by bfophoto, used a process he describes as “brutally tedious.” The results, though: Wow. What you’re seeing are cross-sectional scans of hardwood, burls, and branches sequenced in stop motion. It’s like his camera is moving through the wood.
Foxwell used a milling machine to cut slices from 1/40 inch to 1/2,000 of an inch thick. He cleaned, polished, and applied wood oil to each cross-section before capturing its image with a stop-motion camera. And then on to the next cut.
Time-intensive as that process sounds, another issue—as he notes on his website—is that it’s “difficult to keep from watching stuff like this loop endlessly on playback as you are in the middle of shooting it.”http://www.slate.com/articles/video/video/2017/07/wood_cross_section_music_video_woodswimmer_unpacks_layers_of_hardwood.html?wpsrc=sh_all_dt_fb_top
Thanks to Elisabeth Wheeler for sharing. Enjoy...