Fresnel Lens Reverse Engineering

Fresnel lenses are used in lighthouses all over the world. Specifically, this particular fresnel lens was borrowed from a nautical museum’s storage for reverse engineering. The lens is made up of multiple parts that all fit together. Undeniably every detail needed to be captured exactly, with no room for error.

3D Scanning

The glass areas needed to be sprayed with a micro-thin layer of washable paint so the scanner can detect the surface. For this project, we used Faro blue LLP to complete all scanning on the lens. So the inside could be scanned we needed to gain access to the center of the lens. Since the bulb in the center needs to get changed, there were hinges on the brass that allowed access to the center. So, the faro slipped in easily and was able to capture all data missing from the outside.

Fresnel Lens reverse engineering process

The lens was originally built in many different parts. So, the brass sections needed to be designed individually first. Since most of the brass sections were identical, they could be copied around the entire part. But, the hinged doorway sections were slightly different and had to be designed separately.

Each piece of the glass lens was different from the one above and below. After all the 3D scan data was processed, Cross-sections were taken to accurately capture the original geometry design. Further, threaded holes were modeled in the CAD model and added to attach each piece to its mating piece.

The final model will be used to make at least 1 working replica for display and decor purposes.