CT works when the scanned object is partially transparent to the light. In linked slides I was scanning a beer glass. I used father’s LP record player to have rotation at a fixed speed. Source of light was an LCD screen showing white picture in fullscreen. Fixed record player rotational speed + fixed camera framerate gave me accurate angles to run backprojection. The backprojection algorithm I used for this CT proof of concept is rather unsophisticated. You simply “extrude” each 2D photo in the direction camera is looking at. Then you add up all these volumes from different photos and you’re done. Almost. You can get sophisticated and try to correct for various imperfections of this crude method.

Here are slides in Slovene with photos of my garage CT scanner https://drola.si/demos/ct_prezentacija.pdf

I believe photogrammetry is computationally vastly more complicated than CT but I haven’t gone deep into it yet.