$\mathbf p$. To compute the sign of the distance, we used ray casting to perform multiple tests for each point in order to determine if $\mathbf p$ were inside or outside the surface. This was necessitated by the fact that not all RIV meshes were orientable. On the other hand, significant optimizations were possible due to the fact that, for a given time slice, once an estimate of the greatest radius, $r$, had been found, we only needed to consider other RIVs if their bounding boxes were large enough to contain a sphere of radius $r$. Furthermore, we optimized the search for the largest radius within a given RIV by recursively computing distances at finer grid resolutions in the vicinity of the largest distance value found at the next coarser resolution.

\[comp\]

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   ![image](fit.jpg){width="85mm"}   ![image](wVst.jpg){width="85mm"}
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\[fig3:figlabel\]

Conclusion and outlook
======================

The main goal of this paper was to investigate whether there is an intrinsic obstruction to further reduction of the scaling gap in the 3D Navier-Stokes regularity problem, within the mathematical framework based on the suitably defined scale of sparseness of the regions of intense fluid activity. The idea was to perform a spatially highly resolved computational 