| Table of Contents |
|---|
1. Calculation on first star facet example highlighted with pink
| Note |
|---|
| All calculation are performed in 2D. Model is projected on table facet plane |
1.1 Draw line a through star facet edge belongs to table facet. Line will separate plane into half-planes β and δ:
1.2 Find most distant point (call it B) on star facet from line a. A is point, where perpendicular from point B is crossing line a:
1.3 Find most distant point on girdle (call it D) from line a, point should belong to β half-plane. C is point, where perpendicular from point D is crossing line a:
1.4 Star ratio is |AB| length divided by |CD| length and transferred to percentage view.
1.5 Upper ratio is equal to expression result (100% - Star ratio).
2. Calculation on second star facet example highlighted with pink
| Note |
|---|
| All calculation are performed in 2D. Model is projected on table facet plane |
2.1 Draw line a through star facet edge belongs to table facet. Line will separate plane into half-planes β and δ:
2.2 Find most distant point (call it B) on star facet from line a. A is point, where perpendicular from point B is crossing line a:
2.3 Find most distant point on girdle (call it D) from line a, point should belong to β half-plane. C is point, where perpendicular from point D is crossing line a:
2.4 Star ratio is |AB| length divided by |CD| length and transferred to percentage view.
2.5 Upper ratio is equal to expression result (100% - Star ratio).
3. Star \ Upper ratio parameters in report
3.1 Star \ Upper ratio can be found in Main and Detailed Parameter part of full report, for example:
Main parameters:
Parameter |
| Avg | Min | Max | Dev |
|---|---|---|---|---|---|
Star : Upper ratio | % | 61.39 : 38.61 | 53.29 : 46.71 | 71.25 : 28.75 | 17.96 |
Detailed parameters:
Parameter |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|---|
Star : Upper ratio | % | 59.00 : 41.00 | 63.52 : 36.48 | 71.25 : 28.75 | 58.42 : 41.58 | 61.37 : 38.63 | 64.69 : 35.31 | 59.55 : 40.45 | 53.29 : 46.71 |
3.2 Following bookmark are used for Star ratio:
- STAR_RATIO_PC
- STAR_RATIO_PC_1 - STAR_RATIO_PC_8
- STAR_RATIO_PC_DEV
- STAR_RATIO_PC_MIN
- STAR_RATIO_PC_MAX
3.3 Following bookmark are used for Upper ratio:
- UPPER_RATIO_PC
- UPPER_RATIO_PC_1 - UPPER_RATIO_PC_8
- UPPER_RATIO_PC_DEV
- UPPER_RATIO_PC_MIN
- UPPER_RATIO_PC_MAX
3.4 Star \ Upper ratio can be found in following report types:
- 8-Facet report
- Full report
- Illustrated report
3.5 Star \ Upper ratio is calculated for following cutting types:
- Round brilliant (RBC)
- Round fancies (oval, marquise, heart, pear and etc)
- Cushion
4. Notes
- If you have any question, please ask it in comments or send e-mail to developer.
- If you find mistake, please describe it in comments or send e-mail to developer
In projection on XY plane, for each Star facet:
- Find the most distant point belong to the Start facet from line between Star and Table facets. Call it "A".
- Find the most distant point from this line on the girdle (in the same half-plane). Call it "B"
- StarUpperRatio is A\B.
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