Basics of Coordinate Metrology
Unit 4:  Geometric Elements -Summary

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Summary:

  • In this lesson, the standard geometric elements have been discussed. By combining these standard geometric elements, a large number of parts can be described. Standard geometric elements are also referred to as "prismatic and rotationally symmetric geometric elements".
  • Note: The number of probing points for the standard geometric elements are listed in the table below; to define the coordinate system unambiguously in a three-dimensional coordinate system, there are, for example, 6 of them:
       

Example of the combination of standard geometric elements: Zeiss practice cube.
Geometric element Minimum number of points     Geometric element Minimum number of points
Point 1 Sphere 4
Line 2   Cylinder 5
Plane 3 Cone 6
Circle 3   Torus 7
   
  • Sometimes it is necessary to project the probing points for the standard geometric elements point, line and circle in a plane, before proceeding to evaluate the elements by means of a computer.