I hope that I am reading the question correctly, but you are asking how to build a computer for 3d graphics and animation. Is that correct? If so almost any of the mid range gaming systems will work off the shelf for most softwares and even most of the more advanced softwares. I run simulations on an old Acer Aspire with little issues and relative speed. There are some crash issues if I try to do anything else but that is to be expected from a 10 year old computer. The bits and pieces are up to the individual because budget always plays a massive part. There are no 1 stop answers that say "this one" because just like the modelers the systems have to fit the user.