Hey there.
So you know how a machine (like the workbench) has an animation when doing things?
The furnace doesn’t.
Right now, my mouse is hovering on my furnace, and I have NO information to tell me that it contains items (glue, in my case) in the “Crafted Items” tab.
But I noticed that it also doesn’t play any animation to show that it’s crafting something. There is some information that I can see when I hover my mouse on it, but I’d say it’s not enough.
I would suggest that the furnace crucible could receive an additional 3D model when correctly placed on a furnace base, to have a thermometer that indicates to the player that it’s melting things.
Here’s a very basic and thought-less mock-up of what I mean. When the furnace is melting something, the thermometer’s pin could spin in the red side and the whole thermometer could vibrate slightly.
The idea here would be that this could be an additional model (like how we can have a beard on our character), not a modification to the Crucible model, to make it easier to design.