[zowie_vd]

> Since most artists probably start with a composition in the 2d space of the artwork, there’s never really a coherent 3d space to place the light sources in or figure out those projections in.

Highly skilled artists don't just think in 2D — they really do imagine the 3D scene that they're painting. It's hard to relate to but people with a lot of drawing/painting experience can "feel the form", as they say, when they draw. But it's true that figuring out the lighting is still difficult even then.

I do want to point out that if you look at talented painters from later in history than the early renaissance, they don't make nearly as many mistakes as the ones in the article, although of course the lighting of imaginary scenes is still always approximated and simplified.

[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.