Factorio Forums

I understand that stone furnace doesn't need it, but that one does to easier compare cost with electric.

The raw cost only considers handcrafted materials. Since neither steel nor stone brick can be handcrafted, they are considered the raw materials.

I'm not sure if it's an intended behavior or not... but open tech tree and mouse over it there.
It seems that cost calcualted from tech tree doesn't stop on itermediates and goes all they way to raws.

Showing total raw would be totally(heh) redundant as it would just be a copy of the ingredients list.

You mean like this: It's a pretty neat feature of tech screen.

The technology GUI has no context for "what recipes should I use to calculate total raw" so it just uses them all. As a result you see it decompose things into ore/oil. In the player inventory "total raw" is "total raw using recipes that I can hand-craft" and would show the exact materials used for making the steel furnace.