Another great free alternative is COLMAP (https://demuc.de/colmap).

And for those interested in doing this on mobile in real-time, we've just released a beta SDK (https://abound.dev) that lets you add real-time photogrammetry to any iOS app.

How do COLMAP, Meshroom and VisualSFM compare to one another?

Some stuff that comes into mind:

* COLMAP and Meshroom are able to create a mesh from the pointcloud whereas VisualSFM is not. If you wish to create a mesh out of VisualSFM end result, you could use OpenMVS[1]

* COLMAP does not create a texture file for the resulting mesh - instead it uses vertex color for "texturing"

* COLMAP and Meshroom licenses permit commercial usage - VisualSFM does not (you need to license it)

From these three I've found that COLMAP works the best and VisualSFM comes second. Meshroom has a nice feature that allows you to add images into your model incrementally (I think without complete recompute) but it didn't work that well yet.

What comes to open source photogrammetry in general, my opinion is that COLMAP + OpenMVS or OpenMVG[2] + OpenMVS are the tools to go albeit the command line interface with huge amount of possible options can be a bit tricky at first.

1. https://github.com/cdcseacave/openMVS

2. https://github.com/openMVG/openMVG