I am wondering how to go from an image to a 3D printed part? Does anyone know of such a service? How expensive is the service? I only need 4 aiming sights for my SdKfz 251 Stuka Zu Fuss in 1/35 scale.

Hi Mark, have a look at Shapeways.com - they have a forum with "modeller needed" and "modeller for hire" sections.

The basics are that you need to design the item in some kind of 3D CAD program in order to create the computer model that can be uploaded to a 3D printer. If you have time and inclination you can check out packages like Sketchup and have a go, but otherwise you will need a designer to do the CAD work for you. Price depends on a number of factors, but get a firm quote before committing! Also, check first in case the part already exists - there's no point paying a CAD pilot's hourly rate if the part is already "out there". (The online services like Shapeways and Click2Detail allow designers to set a markup on each item sold, so they can claw back their costs if the item is popular. I've sold items on Shapeways that way, as has Mike Candahay - another Armorama member.)

go to the top of the page & type "3d print" in the search dialog to get lots of discussions about 3D printing on this forum.