ReadonlycenterCentre in world space, copied.
Optional ReadonlyfalloffWidth of the inward edge fade in world units, default 0 (a hard edge).
Finite and >= 0. A value larger than radius is legal and simply means
the weight never reaches 1, peaking at the centre.
ReadonlyradiusRadius in world units. Finite and > 0.
Readonlyshape
An axis-aligned sphere for volumeField.
The weight is
1at distance≤ radius − fallofffromcenter, smoothly ramps to0atradius, and is exactly0beyond it.