OpenDroneMap. It’s a suite that provides photogrammetry, stitching, volumetric analysis, geographic correlation, and 3D model conversion from aerial and non-aerial photos. And that’s only the features that I use myself. It defaults to CPU-only rendering, so you don’t need a big bad GPU to GSD.

Even ignoring the lack of subscription cost, ODM performs at least as well as other applications I tried such as Pix4D. Professionally, I use it for year-over-year kelp bed monitoring, photosynthetic mass analysis, and home construction analysis, specifically volumetric infill needs. Personally, I use it to generate 3D models of my boat interior, which I convert to STL files for arranging infrastructure in limited spaces.