This guide provides a complete photogrammetry workflow, from a physical object to digital 3D model.The aim of this guide is to show that with reasonably low-cost equipment and a bit of effort, anyone can create high-quality 3D models.
The first section covers how to photograph your object. It’s possible to get results from hastily taken photographs, fixed in post, however, I believe there is no substitute for taking good photographs in the first place. It will save you time later and increase the quality of your 3D object.
The second section details how to process your photographs and create your models in Agisoft PhotoScan. There are alternatives to Photoscan out there such as AutoDesk’s ReMake (now ReCap Photo), Reality Capture and 3DF Zephyr. I started using Agisoft Photoscan in 2015 and am still satisfied with the results. There is a free trial version and a one-off fee of $179 after that.
After completing these sections you will have a 3D model which could be prepared for 3D printing or shared online. This guide covers how to prepare models for viewing online in the free and open source Universal Viewer. The third section details how to use Blender (also free and open source) to optimise and align your model before viewing in the Universal Viewer. This section is reasonably complex and covers how to reduce the number of polygons in your mesh and create a normal map.
This guide is a living document and in the spirit of sharing, I appreciate any feedback or comments to enable me to improve it.
Thanks to @edsilv for his help on the 'preparing for the web' section.