如何测量曲面的最大半径（最小半径可直接测）？

如何测量曲面的最大半径（最小半径可直接测）？

Minimum Maximum Radius Curvature
  
In general, each section curve in the family will have a different radius of curvature at the point P. The smallest of these radii is called the Minimum radius of curvature of the face at the point P, and the largest is called the Maximum radius of curvature of the face at the point P.
  
The minimum radius tells you how large a sphere can be placed in contact with the face at the point P without gouging. This can be useful in choosing NC cutting tools.
  
The Mean radius of curvature is the reciprocal of the mean curvature, which is the average of maximum and minimum curvature. If we let "r" and "R" denotes the Minimum and Maximum radii of curvature respectively, then the Mean radius of curvature is (2rR) ?(R+r), and the Gaussian radius of curvature is . (Remember, the sign of r and R is dependent on the direction of the face normal vector N.)
  
The radius of curvature values will be positive or negative depending on whether the corresponding planar section is concave or convex. In particular, this means that Gaussian radius will only be negative at "saddle" shaped points (where one section is concave and the other is convex).
  
The sign of the numbers that are output tells about the convexity or concavity of the face. For example, if the face is convex, the Minimum radius of curvature will have the same sign at all points on the face. The Gaussian radius will only be negative at "saddle-shaped" points where the Minimum and Maximum radii of curvature have opposite signs (i.e., rR<0).
  
The face analysis results can be used qualitatively and quantitatively. For quantitative analysis, only the Minimum Radius results can be used to decide the maximum tool radius that can be used for machining purposes.

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