OP, it's not as nightmarish as you may get the impression from that anon who replied. There are a handful of very good BJD artists who do their work in 3D sculpting programs and then do produce wonderful physical versions of it, the ones who come to mind are Batchix and SiO2. The latter is a Chinese company and you can check out both their dolls and the prototype 3d models, the former is a Western artist you can probably easily chat with on instagram @batchix or tumblr @batchixdolls who is rather nice and would be happy to give you tips. Similar Western creators who might be willing to answer questions about this are Armeleia and Buffdolls (probably google will bring up their tumblr and instagram), though they don't produce full dolls, just parts. They have all been at their crafts for a decade or more and are well-respected and successful.
The pitfall of many creators, especially who work in 3D and try to create a physical doll from it, is inflexibility. Be open to feedback. Also, you can try posting over at the BJD general
>>6465276, as you can see from the person who asked for crit yesterday and got quite a lot of detailed feedback, we're not assholes if you genuinely are receptive to feedback.
>>6474874......Kayke, is that you? Kind of sounds like it. (Kayke was artist who created pic related, sent out non functional versions of it to people who preordered, and was mad when /bjd/ disapproved of her work and business ethic.) Your problem was that you accept money for prototype-quality flawed work, went immediately to the selling sculpt stage without a couple years (at least!) of learning and practice, and take feedback very poorly.