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When using the built-in primitive ellipsoid shapes, the underlying mathematical function is such the resulting blended surface has approximately the same volume as the constituent primitives. This makes this workflow an excellent choice for modeling things like viscous fluids, where this volume-preserving property is highly desirable. However, as mentioned above, there is no fine control over how the shapes are blended together: either the primitives interact and blend, or they do not. The threshold at which they blend can be set globally for the entire surface (which will cause the entire implicit surface to "bulk up" or "shrink down"), but the threshold cannot be set on a sphere-by-sphere basis.

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