Source: https://guthlabs.ai/docs/instruments/3d-solid-volume-surface-area-calculator/implementation/

instrument implementation / implementation-contract

# 3D Solid Volume/Surface Area Calculator implementation

A source-bound implementation contract for 3D Solid Volume/Surface Area Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-177

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not state torus validity regimes or spindle-torus handling, so inputs with R<r can produce a plausible but geometrically inappropriate result. Extreme sphere radii also overflow the volume in ordinary JavaScript Number arithmetic, and negative cone heights expose an unstated sign convention.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "solid_type": "sphere",
    "radius": 3,
    "length_unit": "m"
  },
  "expected_outputs": {
    "volume": 113.09733552923255,
    "volume_unit": "m^3",
    "surface_area": 113.09733552923255,
    "surface_area_unit": "m^2"
  },
  "working": "V=(4/3)πr³=(4/3)π(3³)=(4/3)π(27)=36π=113.09733552923255 m^3. SA=4πr²=4π(3²)=36π=113.09733552923255 m^2."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/3d-solid-volume-surface-area-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/3d-solid-volume-surface-area-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/3d-solid-volume-surface-area-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`