Helium help : Comprehensive list of report parameters
Position normalization

Applicable to:

  • Brilliant
  • Rounded Fancies / Marquise, Oval, Pear

Brilliant

Before estimation of the cut parameters the position of the model is normalized. The model is rotated in such a way that the normal to the table facet becomes vertical, thus the table facet is placed strictly horizontally.

Then the azimuth of the main pavilion facets is normalized. The model is rotated around the vertical axis to make the azimuth of one of the main pavilion facets equal to zero. The software chooses one of the eight main pavilion facets. It analyzes the parts of the model that correspond to each main pavilion facet and chooses the one that has the most deviation from the others. Thus the software tries to find the defects in the model symmetry and put the model in some definite position. If the same stone is scanned again, it will be positioned in the same way with high probability. Please note, that the more symmetrical is the stone, the more probable it will be positioned differently in different scans.

As the table facet is placed horizontally, all facet's slope angles are measured relative to the table facet. As one of the main pavilion facets is set to the zero azimuth, all facets' azimuth angles are measured relative to that reference pavilion facet.

Rounded Fancies (Marquise, Oval, Pear)

Before estimation of the cut parameters the position of the model is normalized. The model is rotated in such a way that the normal to the table facet becomes vertical, thus the table facet is placed strictly horizontally.

The software measures diameters of the model with the step of 0.5 degrees and finds the direction of the maximum diameter. The model is rotated around the vertical axis to make this direction the 90 degrees azimuth. There are two possible positions of the model that puts the direction of the maximum diameter as the 90 degrees azimuth. The software analyzes two parts of the model that correspond to opposite directions and chooses the one that has the most deviation from the model's center. Thus the software puts the model in some definite position. If the same stone is scanned again, it will be positioned in the same way with high probability. Please note, that the more symmetrical is the stone, the more probable it will be positioned differently in different scans.

As the table facet is placed horizontally, all facet's slope angles are measured relative to the table facet.

DiamCalc Brilliant Cut Parameters