"Gauss curvature" node

Слиты nikitronn запросил слияние gauss_curvature в master

Created by: portnov

This node calculates Gaussian curvature (https://en.wikipedia.org/wiki/Gaussian_curvature) at a given point of surface.

  • For points where the surface is shaped like sphere, Gaussian curvature is positive;
  • For "saddle points" of the surface, Gaussian curvature is negative;
  • If the surface is "flat" at the given point in one or two directions, then Gaussian curvature is zero;
  • The more "bent" the surface is at the given point is, the bigger the absolute value of Gaussian curvature will be.

Note that the calculation is done by numerical differentiation, so it may be not very precise in some cases.

Screenshot_20200502_190030 Screenshot_20200502_190251 Screenshot_20200502_190330 Screenshot_20200502_191317

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