SSE Looking to make a body mod for a custom race. Any pointers?

[SixT4]

I've been meaning to make a custom race for quite some time now, and it looks like I'm going to be making the body from scratch now to avoid a permissions fustercluck- I refuse to ask any author for permission; not like they'd actually give it, nor do I want to be needlessly restrictive like most of the NexusMods community.

 

So, I must ask:

Are the existing body mods made from scratch, or are they edited from the default body? Or, are they first generated in something like MakeHuman and then edited?

 

Thank you in advance.