mim shin

i got i7 4790k and gtx750ti should i use dx or gl? what should i use for thickening my model? vox layer or coat? how to bend volume along a curve ? like this:

hi i asked this in zbrush forum but nobody answer me so i ask here although its not directly relate to 3d coat but i know there are many zbrush user in this forum too ! here is my question: how can i convert a zbrush brush (zbp) to obj file format to be usable in 3dcoat?