<p>From what I understand, UV curing of resin prints works by starting a chemical reaction that hardens the resin permanently.</p>

<p>Also, a curing step after print is needed to speed up the print and also to reduce the curing during print, which would cure resin beyond the current layer.</p>

<p>However, what is the transmissivity of UV light in partially cured prints? If I print a more massive object, or if I use an opaque resin, how deep will the object harden properly? Absorption is always exponential, meaning that it decreases quickly with depth.</p>

<p>Depending on the resin, how thick prints can be effectively cured? This information is not provided with the resin, which I actually would expect from reputable manufacturers.</p>

In terms of Cura's model for showing overhangs, I'm nearly sure it's just the ratio - rise over run, or rather run over rise. And indeed that's what makes sense mathematically:
At least some portion of the wall extrusion in layer N+1 needs to sit on top of the corresponding wall extrusion in layer N. For a given 3D surface slope, the "run" - the distance the cross-section moves from one layer to the next, which needs to be bounded by some fraction of the line width - varies proportionally to the "rise" - the layer height.