[CadmiumYellow]

It's a skillset that gives you a very different way of perceiving the world. I find it difficult to describe but "feeling the form" feels close to my experience while drawing. When I haven't drawn in a while and I pick up a pencil my first few sketches are always stiff, awkward, and cartoonish. It's like I'm drawing an emoji or a logo or something. Then after a little while I remember how to feel the form again and I start to be able to articulate the shape and the weight of an object and translate that convincingly to the page. It really isn't thinking in 2D, per se, it's thinking in...flattened 3D maybe?

To your point about painters from later in history, I think once linear perspective was codified and became more widespread it made the process of projecting shadows much easier for artists. In a lot of renaissance artwork you can actually map out the perspective lines to find that the artist was working with multiple incompatible vanishing points, hence the wonky spatiality of many of the paintings from that era.