In the most recent update posted to the Shroud of the Avatar website, Portalarium revealed the very complex crafting sigil:

This sigil depicts the fifteen crafting skills that will be featured in Shroud of the Avatar, as well as their relationship to each other.

The innermost ring of the sigil is the gathering ring, and displays the five skills that will supply players with raw materials for crafting. These skills are: Mining, Forestry, Agriculture, Field Dressing, and Foraging.

The middle ring of the sigil is the refining ring, and displays the five skills that allow players to transmute raw materials into crafting components. These skills are: Smelting, Milling, Textiles, Tanning, and Butchery.

The outer ring of the sigil is the production ring, and displays the five skills that allow players to combine crafting components into finished products. These skills are: Blacksmithing, Carpentry, Tailoring, Cooking, and Alchemy.

So, for example, here is one possible crafting pipeline:

For instance you use Mining to get Ore. You then smelt that Ore into sheets, wire, ingots, and sword blanks. Finally you use those smelted items to create weapons, armor, and tools.

It should be noted that there is a mismatch between the number of crafting skills and the number of crafting stations. This is due, in part, to the fact that the gathering skills do not have corresponding crafting stations; raw materials are gathered during normal gameplay (e.g. by cutting down a tree). Additionally, the Textiles refining skill likely incorporates both Spinning and Weaving, each of which has a separate crafting station.

You can find the above information in a more permanent home, along with additional crafting-related information, at the Ultima Codex’s Shroud of the Avatar crafting page.