Description
Return top/bottom perspective-line separations and their difference.
Artwork measurements distinguish physical dimensions, projected regions and scale conventions. Length, area and volume change with different powers of a scale, while frame overlaps and crop geometry depend on which boundaries were measured. A numerical fit does not identify an artwork or establish its historical interpretation.
Return top/bottom perspective-line separations and their difference.
When to use this tool
Use Perspective Exercise Measured Convergence Gap when checking the stated artwork dimension, crop, frame or scale relation.
How to use the tool and how it works
- Enter firstTop, firstBottom, secondTop, secondBottom. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read topSeparation, bottomSeparation, convergence. Use the output convention below.
Return top/bottom perspective-line separations and their difference. Each separation is the absolute gap between supplied positions; convergence = bottomSeparation-topSeparation.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstTop | First Top | Required. Finite number. |
| firstBottom | First Bottom | Required. Finite number. |
| secondTop | Second Top | Required. Finite number. |
| secondBottom | Second Bottom | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| topSeparation | Top Separation | Required. Finite number. |
| bottomSeparation | Bottom Separation | Required. Finite number. |
| convergence | Convergence | Required. Finite number. |
{
"input": {
"firstTop": 4,
"firstBottom": 0,
"secondTop": 6,
"secondBottom": 10
},
"output": {
"topSeparation": 2,
"bottomSeparation": 10,
"convergence": 8
}
}Limitations and assumptions
- This is one projected measurement convention, not a vanishing-point estimate, perspective reconstruction or assessment of artistic correctness.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Inspect the original object, measured boundaries and appropriate complete geometry or catalog record for physical or historical conclusions.
References
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