How is a consumer product made?

How are consumer products that are made to fit existing consumer products made? Like cases for an iPhone, or protective shells for a specific laptop model; how are they designed and manufactured to exactly fit the product? Would they do a 3D scan of an iPhone then import it into SketchUp for example and create it around the relief of that ready to be formed in plastic?

I aks because I'm thinking of making a product that will fit an existing product, but I'm not sure how to make it fit perfectly.

The moment when a model is released, other small companies buy one and take measurements and make all the accesories it needed. They use ofcouse scanning and make the products in surplus. I don't think you can make one because it need expensive tools to make it.since the companies are making in surplus, it donest cost much for them for the tools, for you, on the other hand ll cost more!

  • Will an Iphone work with consumer cellular? I'm going to buy an iphone 4s from somebody off of craigslist. It is an unlocked iphone that was previously used on at&t, and I was wondering if it would work on my plan for consumer cellular. I plan to just insert my sim card into the phone, and have it work. Will that be the case? If it's not the case, please explain how i will ave to do it. Also, if I can't, tell me why.
  • What's the difference from an OEM product and an original product? I need a new charger for my iPhone and I don't know if I should go buy an OEM charger from eBay or go buy an actual apple charger from Walmart that's going to be way more expensive. Since OEM is basically the same thing without retail packaging, would there be a difference in quality?
  • What's the difference between a international made iPhone and US made iPhone? I plan on buying or trading my iPhone 4 for a new iPhone 5C on Craigslist or at my local phone shop. Plus, can I flash a unlocked iPhone on to any carrier like PageOne or revol wireless?
  • Is national consumer center really giving me a free iphone 5? So I was on my coke awards and all of a sudden this website add said that 'I just won a free iphone 5' and they want my mailing info are they like real? Or is it just some random pop up add that isn't to trust? what do I do? Please help! And the site is called National Consumer Center