Over in the Projects forum i shared how I used a technique called photogrametry to create scans of an object from photographs.
I figured I’d make a new thread to show a bit more of the photogrametry process for anyone interested.
Here’s a screenshot of the resulting STL from a pair of Raybans I scanned using photogrametry.
Photogrametry software doesn’t work on glossy or transparent objects. It also needs lots of small details for the software to reference.
I’ve found it works best when I spay the parts with a washable chalk spay and then use a toothbrush to create splatters.
You should be able to walk around your object to take photos, however I got the best results when I shot the object on a green screen with a turntable.
Photogrametry software expects to see the background move with each change in angle. The creases in the green screen will mess up the software so
I used a Photoshop batch command to delete the green screen in my photos.
Having a detailed 3D scan is especially useful on parts that have compound curvature or geometry that’s difficult to measure.
I tried both Meshroom (free) and Autodesk RePhoto (paid) and got simmilar results from both.
The resuting scans seem to be quite accurate. I don’t have a way to measure accuracy but I’d guess they’re about +/- 0.2mm.
Not bad for free software!
Here’s a great video from Prusa that explains the process in more detail.