We represent a moving person with a canonical appear-
ance volume Fc warped to an observed pose to produce out-
put appearance volume Fo:

Fo(x, p) = Fc(T (x, p)),

(1)
where Fc : x → (c, σ) maps position x to color c and den-
sity σ, and T : (xo, p) → xc defines a motion field mapping
points from observed space back to canonical space, guided
by observed pose p = (J, Ω), where J includes K standard
3D joint locations, and Ω = {ωi} are local joint rotations
represented as axis-angle vectors ωi.
HumanNeRF- Free-viewpoint Rendering of Moving People from Monocular Video