About this 3D model

I love fisheye lenses, both for artistic and technical purposes, and I have quite a collection from door peepholes to high-quality fisheye lenses. Unfortunately, few cheap options give full 180-degree views, and almost none give more than 180. Here's a simple part to allow mounting an old 185-degree converter (originally sold by IPIX for use on a long extinct 1.3MP Olympus) on a 16MP Canon PowerShot A4000. You might not have either this lens or this camera, but the mounting method easily can be adapted for many camera and adapter lens or filter combinations....