On the lawn of the Pettigrew House & Museum in Sioux Falls, South Dakota is a large petrified tree stump. It stands roughly between two and three feet tall. It is hollow, but I was unable to get clear photos of the bottom of the hollow from the right angles high enough to model it. It was acquired by Senator Pettigrew for his burgeoning private collection which was eventually turned into a private museum.
I created this model in Agisoft Photoscan Pro.
I took 52 photos around the tree stump with my trusty Nikon D200. I used my preferred lens, a manual focus nifty fifty. I set my Nikon to Aperture Mode and shot in RAW format. I used an f/16 setting to avoid chromatic artifacts that sometimes occur at f/22, but sacrificed a tiny bit of background sharpness.
At home, I imported all the RAW photos into Adobe Lightroom. I checked each photo for exposure and detail and made any necessary corrections. After finishing the corrections, I exported the photos as 16-bit TIFs.
I'm not very good in Photoshop (yet) so I use Photoscissors for Mac to help me create masks for each photo. Photoscissors is more forgiving and generally easier for me to use right now. After I finish each mask, I export it as a PNG.
Finally, I import both the TIFs & PNGs into Agisoft Photoscan Pro. I generally use either the high or ultra-high settings to get the best results. I then go do housework while I give my Macbook Pro an hour or two to go from a sparse cloud to dense cloud to creating a mesh and finally a texture map.
I'm still learning a great deal about how to model in 3D so I tend to leave my models somewhat unfinished once Photoscan is finished creating it. I figure if someone likes one of my models enough to use it, hopefully they'll be able to fix any errors or holes in it.