[skye-adaire]

>Are there applications you have in mind where the distance to the nearest surface is actually useful, regardless of the surface representation?

Distance fields are a subset of implicit functions (see wikipedia). The use of level curves (which can be interpreted as "distance" for SDFs) is broad. You can dynamically and trivially thicken or shrink objects by adding or subtracting to the distance. Functions defined on the level curves output of an SDF can be used to map a volume to another implicit function (see nTopology). With implicit functions, the non-zero level sets are really just as important, but most focus on the zero level set in rendering.

>There's a subtle difference here because you actually need the closest point (not just the distance) so that you can look up a boundary condition.

Vector to Closest Point (VCP) is subtle but different in important ways. It is unsigned, and cannot indicate whether a position is inside or outside the object. Implicit modeling is not generally concerned with parameterizing the surface, since we can use volumetric, 3D procedural textures.

[dartmoose]

Thanks for the insights! I come from a mostly rendering background, so my understanding is definitely biased from always thinking of SDFs in the context of surface rendering or reconstruction :-)