As I was photographing the rapids and falls at Falls Park in Sioux Falls, SD, I came across this striking and beautiful example of fossilized sand ripples in the Sioux quartzite.
This wonderful stone is among the oldest rock in North America. It started out as sandstone and was gradually turned into quartzite. Much of what is now exposed across eastern South Dakota and western Minnesota was uncovered by the last glaciers in the region.
Normally this particular example would be difficult to reach or see as the Big Sioux River covers the riverbed around it. The river was low and I was able to walk out onto the dry riverbed and spotted this. It is incredible to think that this was already in existence millions of years before the dinosaurs!
When I stumbled across this beautiful rock formation, my camera was already running low on battery. I shot ten photos over and around it, but I still managed to miss a few small spots here and there.
I usually shoot my photos in RAW format. I do this to capture as much detail and information as possible. RAW format will let me even out the exposures, capture lost detail in shadows and recover blown out highlights. It also gives me the greatest latitude for adjusting the colors to what I think will look best for the model.
After doing all my photo corrections and adjustments in Adobe Lightroom, I exported the ten photos as JPEGs at high quality, full-sized. I then imported all the photos into Agisoft Photoscan and used the 'High' setting for initial photo matching and building of the rough draft model. For the dense cloud, I chose 'Medium' and quickly created a great model with greater detail. For the mesh creation, I again chose 'Medium' and finally created a texture to drape over the model.
In this particular example, I chose lower quality settings as I'm using a Mac Pro with only four GB of RAM, so I didn't want to overwhelm my Mac. (I'll be buying more RAM next month so I can create higher-quality models).
While I'm getting better at creating 3D models using photogrammetry, I'm still very much a novice when it comes to creating a support beneath a hollow model like this. I'd strongly urge anyone who wants to print this model to spend some time adding a rear support to it.