As others have said, if you want to replace an existing part, it's probably actually better to redesign it. I use OpenSCAD to do simple 3D designs in code. It's easy to get started if you're a developer.
As for scanning, I've used Trnio on iPhone for artistic scans. e.g. I scanned my dog and printed a tiny replica. My nephew thought it was a pile of melted yogurt, but I knew what it was. :-)
As for scanning, I've used Trnio on iPhone for artistic scans. e.g. I scanned my dog and printed a tiny replica. My nephew thought it was a pile of melted yogurt, but I knew what it was. :-)