[gavanwoolery]

had an idea to scan semi convex objects using a web cam and a green screen (something like this has probably been done before Im guessing). Just trace the outline of the object at various rotations (i.e. using a turn-table) and produce a model from the result. Probably do two passes, rotating the object 90 degrees on its side for the second pass.

[saganus]

There was a software in the 90s or early 2000s called "Sculptor 3D" that did precisely this.

You would print a sheet of paper that had location marks, then put in the center whatever object you wanted to model and take pictures of it from different angles.

Then you would manually select each marker (in order, so the program could determine where was this picture taken from) and finally you would outline the object you were interested in.

The program would then process everything and extract a 3D model out of the pictures including textures.

It was pretty amazing for the time, so I'm guessing nowadays this should be much more doable.

They even had a free version distributed in a 3D design magazine, unfortunately due to the very common name it's being very hard for me to find any references to it.

[joshvm]

Yup, this is called shape from silhouette. Quite a lot of research on it over the years:

https://www.cvg.ethz.ch/teaching/compvis/2011/lecture/vision...

EDIT: Better link

[eon1]

See also: Visual Structure from Motion, which I believe works off static light sources (same stuff you see in 123D Catch and similar software, this one is free though).

http://ccwu.me/vsfm/

For a less detailed/easier to use process, you can also try Regard3D: http://www.regard3d.org/

[jsch]

Another open-source, full 3D reconstruction pipeline is COLMAP: https://colmap.github.io/