# Supplied CAD licenses and clasp investigation

Checked **2026-10-11**. **Design discussion only — not for manufacture.** No supplied CAD body files were downloaded, opened, parsed, adapted, rendered or redistributed. Public listing text, terms and supplier catalog facts were researched. The companion `licenses-clasp.json` separates listing claims, actual unknowns and independent study assumptions.

## Decision before touching CAD assets

**Do not ingest either supplied CGTrader model into this AI-assisted workflow without additional written permission. Do not publish derived STEP or extractable web meshes under the standard license.** There are two distinct issues; neither is resolved merely because a download is free.

1. **AI use requires clarification, not an exaggerated claim.** [CGTrader terms](https://www.cgtrader.com/pages/terms-and-conditions), §21B.1, say: “Product use for machine learning or training of neural network models, including generative AI models, is not permitted.” §19.2 separately restricts free models used for machine learning/training. This clearly excludes training; it does **not explicitly settle every inference-only inspection, AI-directed local CAD script or AI-assisted adaptation scenario**. No-training inference must not be assumed to be either categorically prohibited or affirmatively authorized. For this project, permission is unresolved, so acquisition/ingestion stops here.
2. **Public reusable geometry is a separate, decisive barrier.** Definition 8 limits an *Incorporated Product* to a use from which the model cannot be extracted as a stand-alone object without reverse engineering, and which does not allow further distribution outside the incorporating work. §§21A.2 and 21A.6 prohibit non-incorporated republication/redistribution. §21A.3 requires commercially reasonable protection against access in software. Public STEP, STL or directly exposed mesh arrays in this viewer are reusable geometry, not protected rendered imagery. Converting the file format, modifying the setting or combining it with an original bracelet does not establish compliance. Removing a download button while serving raw mesh data does not fix this.

### What the license does and does not establish

| Intended activity | Current conclusion |
|---|---|
| Machine-learning/neural-network training | Prohibited under No AI; free-file restriction also applies. |
| AI-assisted inspection, adaptation or rendering | Inference-only scope unclear; obtain written clarification before ingestion. |
| Conventional non-AI still/video rendering | Generally contemplated as Incorporated Product in §21A.2, subject to all other terms. No AI is not a blanket ban on ordinary rendering. |
| Conventional non-AI modification | §21A.4 permits derivatives only within Incorporated Product limits; not unrestricted redistribution. |
| Public downloadable STEP/STL incorporating supplied geometry | Additional rights required; do not publish under standard terms. |
| Public viewer with extractable supplied/derived webmesh | Additional rights required for this implementation. |
| Independent original CAD, without supplied asset geometry | Usable project path; clearly label schematic assumptions and do not claim adaptation/file inspection. |

Sections 20.4–20.7 preserve seller copyright and restrict license transfer and where effective additional seller terms may appear. Sections 23A/23B describe custom-license terms; §24 confirms free products still carry the selected license. §19.1 also prohibits reverse engineering. A friendly comment or off-platform note should not be treated as overriding these terms: obtain properly documented rights, including any required CGTrader confirmation. This is a conservative workflow decision, not legal advice. Recheck terms before any later acquisition.

## What is actually known about the supplied assets

### [Emerald Cut Four Prong Solitaire Engagement Ring](https://www.cgtrader.com/free-3d-print-models/jewelry/ring/emerald-cut-four-prong-solitaire-engagement-ring)

- Creator **CADia**, listing ID **7411889**; label **Royalty Free License(no AI)**.
- Listing advertises STL, PDF and 3DM; units “Millimeters”; “Split into parts: 6.” These are **listing metadata, not verified file units or component counts**.
- Seller describes four pointed prongs, tapered cathedral shoulders, a rounded shank and an open center setting, and claims customization/manufacturing readiness. No physical manufacture or CAD validity was verified.
- Actual bounds, stone seat dimensions, solid/mesh/B-rep structures and design history are unknown. **A 3DM file is not automatically parametric**: it may contain fixed surfaces, solids, meshes or other data without editable construction history.
- A ring basket is not a demonstrated bracelet setting. Removing the shank, creating link attachments, accommodating separate diamond/ruby depths, securing emerald-cut corners and proving joint clearance would require an independently engineered adaptation after permission. No basket suitability or articulation claim is made from pictures.

### [Tennis bracelet box clasp FREE](https://www.cgtrader.com/free-3d-print-models/jewelry/bracelet/tennis-bracelet-box-clasp-free)

- Creator **gherman**, listing ID **5166280**; label **Royalty Free License(no AI)**.
- Listing advertises STL, OBJ, 3DM and FBX; “Millimeters”; “Split into parts: 42.” Again, **not file-inspected**.
- Seller says Gemvision Matrix, fixed geometry, and **2.0 mm round-cut diamonds**, with gold weight estimates and a claim of previous manufacture. This does not establish suitability for an approximately 8 mm emerald-cut bracelet or Pt950/Ru.
- Actual tongue/box geometry, two independent external safeties, overlap, connection positions, operating clearances and motion are **unknown**. No mechanism was inferred from listing pictures.
- A direct page read returned an AWS WAF challenge. The parent's earlier successful public listing-text retrieval supplied the metadata above; no access control was bypassed.

### Deferred lawful inspection, if permission is obtained

Record the actual file name/checksum and license grant; use `rhino3dm` for 3DM contents and CadQuery/OCCT where appropriate. Inspect units, full and per-component bounds, layer/object structure, geometry types, open/closed solids and any actual history. Do not equate rendered appearance, part count or a printable flag with solid validity. For a setting, establish stone seats and corner support from geometry; for a clasp, identify box, tongue, both safeties and end connections as separate actual parts. Measure closed connection-datum span, insertion overlap, opening sweeps and interference. All these fields remain null/unverified until real permitted inspection; none can be supplied from a listing photograph.

## Established supplier leads, not an approved mechanism

### Best near-width lead: Stuller hidden box clasp with double safety

[Stuller 21346/66673](https://www.stuller.com/products/21346/66673?groupId=12517) is officially titled **“14K Yellow Gold 9.5x7.5 mm Hidden Box Clasp with Double Safety Catch.”** The official page's metadata states **9.5 × 7.5 mm**. Indexed official specification text calls these approximate length **9.5 mm** and width **7.5 mm**. This is useful catalog envelope evidence near the intended bracelet width, **not a dimensioned engineering drawing**.

What this supports:

- An established finding supplier has a marketed double-safety box-clasp product near the requested width.
- Its referenced variant is **14K yellow gold**, not confirmed platinum.
- The catalog provides a two-dimensional approximate size pair.

What it does **not** support:

- The exact datum/extent of that size pair, whether width includes closed safeties, or height.
- Verified **two independently closing external** safety latches and their positions. “Double Safety Catch” is the supplier's title; obtain an open/closed drawing to confirm the exact requested architecture.
- Box cavity, tongue length/width/thickness, overlap, catch engagement, button stroke, latch sweep, clearance, force, fatigue performance or connection geometry.
- The net clasp contribution to bracelet length. **Do not automatically add 9.5 mm to the stone section.** The relevant quantity is assembled connection-datum span, accounting for overlap and end connections.
- Availability or mechanical validity in Pt950/Ru.

A dynamic browser attempt could not run because the local browser relay extension was unavailable. The accessible official metadata and indexed official specifications support only the limited claims above; no hidden endpoint, login or bypass was used.

### Other leads and exclusions

| Supplier/product | Reliable accessible evidence | Why it is not an approved answer |
|---|---|---|
| [Stuller 21350/250060](https://www.stuller.com/products/21350/250060?groupId=12525) | Official “Box Clasp with Double Safety,” 14K yellow gold, **11 × 10.5 mm** size pair. | Wider than an ~8 mm target; axes/datum convention, height, internals, external-latch drawing and Pt950/Ru availability unverified. |
| [Stuller 21346/100947](https://www.stuller.com/products/21346/100947?groupId=12517) | Official hidden box clasp with double safety, **6.7 × 3.2 mm**, 14K white gold. | Smaller family reference, not a proven suitable assembly. Do not transfer indexed replacement-tongue dimensions or compatibility to the larger SKU. White gold is not platinum. |
| [Otto Frei square box safety clasp](https://www.ottofrei.com/products/gold-square-box-clasp-2-2mm-x-8-0mm-figure-8-safety) | Indexed official description: **2.2 × 8.0 mm**, a figure-8 safety lock, **two closed rings**, 14K yellow/white or 18K yellow gold. Direct read returned HTTP 403. | Two connection rings are **not two safety latches**. Only one safety established; size-axis conventions and full length unknown. Reject as satisfying the two-safety requirement. |
| [Ross Metals Double Tongue Snaps](https://rossmetals.com/products/tongue-snaps-plates-boxes-10k-14k-18k-white-gold-platinum-sterling-silver-tn6-tn9) | Official title has **.031–.040 inch**; official TN6 asset label includes platinum. | Component inquiry only. “Double tongue” is **not two external safeties**. Dimension meaning, alloy/temper and complete matching box unknown; do not mix with an arbitrary Stuller clasp. |
| [Rio Grande square box safety clasp](https://www.riogrande.com/product/sterling-silver-square-box-safety-clasps/694956GP) | Indexed official text explains spring tongue and hollow box; direct page HTTP 403. | No verified two-safety dimensional specification; not selected. |

**No fully specified Pt950/Ru, two-external-safety, near-8-mm production clasp was established by the accessible evidence.** This is the exact specification gap, not permission to invent its mechanism.

### Supplier CAD licensing matters too

[Stuller Terms and Conditions](https://www.stuller.com/terms-and-conditions/), **“Copyright and Design Protection (Including AI Use Restrictions),”** expressly prohibit reproduction, modification and derivatives of website designs/images, including using images to create 2D/3D jewelry models. Their ecommerce guidelines also restrict unauthorized image/description usage. Therefore these products are **procurement/dimensional-reference leads only**, not assets to trace or reverse-model. No Stuller images, CAD or replicated geometry are included. No permissively licensed supplier CAD/download was found. Request explicit rights for any eventual supplier file, especially public download/extractable webmesh use.

## Recommended independent fit-envelope placeholder

Until a jeweler/supplier provides the missing specification, show an **original, amber, conspicuously labeled “CLASP SCHEMATIC — NOT A VALIDATED MECHANISM”** with a schematic box, tongue, **two separate external safety latches** and two end connections. It is not the supplied CGTrader clasp and not a replica of a Stuller design.

An optional independent discussion assumption is a **12 × 8 × 4 mm body**. Those numbers are **not sourced supplier dimensions**, not manufacturing dimensions and not proof that the real clasp will fit. Parent CAD may choose another explicit assumption. Safeties, button and end connections need separate total outer bounds and opening envelopes; they must not silently fit inside the nominal body envelope. Any tongue overlap, wall thickness, spring shape and clearance used to make a visible schematic is an assumption, never a supplier-approved value.

For length arithmetic, measure between the schematic's assembled connection datums. Do not sum box plus tongue lengths without subtracting their actual overlap. Report this as **assumed schematic clasp contribution**, distinct from the **215.9 mm target stone section excluding clasp**. The user's wrist is only guessed at **8 inches or slightly less (203.2 mm upper reference)**; width and front-to-back thickness are unmeasured. This is not a personal-fit validation. An illustrative oval may show the estimate with the cross-section limitation visible.

## Pt950/Ru constraints

Pt950/Ru means a proposed 95% platinum / 5% ruthenium alloy, pending Elena's approval; “platinum” or “white gold” in a catalog does not establish that alloy. [Primary research on platinum jewelry casting](https://technology.matthey.com/content/journals/10.1595/147106705X58268) compares Pt-5%Cu and Pt-5%Ru and describes Ru alloy's common use in hand-working/machining. It does **not** validate a clasp spring.

The box, spring tongue, pins and safety latches may require different processing or even different approved alloys. A gold mechanism must not simply be recast in Pt950/Ru and called equivalent. Supplier/jeweler must specify composition, stock condition, temper, work-hardening/heat treatment, joining limitations, retention/release force and fatigue performance. Material suitability and any mixed-alloy exception require approval; no spring-force or service-life claim is made here.

## Questions for the supplier/jeweler

1. Which exact SKU/revision has **two independent external safety latches**, and can you provide open/closed dimensioned views?
2. What are closed body L/W/H and the total envelope including both safeties and release button? What are tolerances and finish allowances?
3. What are the internal box dimensions and tongue length/width/thickness, insertion overlap, engagement depth and release travel?
4. What is the **closed end-connection datum span** contributing to bracelet length? Specify rings/lugs/pins, holes, articulation axes and maximum rotation.
5. What are each safety's axis, catch engagement, closed projection and full opening sweep? How much finger/tool clearance is needed?
6. Are **all** components available in Pt950/Ru? If not, what alloy/temper is each, and why? Supply material certificates and joining instructions.
7. Is it a matched assembly? What testing supports pull retention, release force, fatigue cycles and accidental-opening resistance?
8. What maintenance, wear inspection and repair/replacement protocol applies?
9. May CAD be inspected through AI-assisted local tools and published as public STEP/STL/extractable webmesh? Provide a specific written license; private access alone does not grant redistribution.

## Draft permission request — not sent

> To CADia / gherman and CGTrader licensing support:
>
> I am preparing a non-production bracelet design-discussion study. The relevant product is [insert the exact listing URL and model ID above]. Before downloading any model files, please confirm whether the following workflow is permitted and provide an effective written/custom license where necessary.
>
> The workflow uses a generative-AI coding assistant to direct local CAD inspection and adaptation, with `rhino3dm`/CadQuery or similar deterministic tools. Model-derived measurements, geometry summaries and potentially renderings may be exposed to the assistant for inference. The project does not intentionally train or fine-tune an AI model on your assets. Please explicitly state whether that inference-only workflow is authorized under the No AI restriction and what restrictions apply to the AI provider's processing or retention.
>
> For the ring, proposed work includes separating/removing the shank, adapting the basket to measured emerald-cut stones and adding bracelet connections. For the clasp, proposed work includes inspecting the actual box/tongue/two-safety architecture and adapting permitted geometry to a bracelet. Please confirm modification rights and any limits; do not assume these modifications are already validated for manufacture.
>
> The intended public deliverable includes rendered images **and reusable geometry**: browser-visible/extractable meshes plus downloadable modified STEP/STL and potentially source files in a public repository. Please expressly grant or deny redistribution and downstream use of that geometry, including derivatives. Permission to render still images alone will not cover this deliverable.
>
> Please identify the rights holder, required attribution, applicable fees, approved hosting/redistribution scope, downstream license and any physical manufacturing limitations. Please also confirm the grant is effective under CGTrader §§20.7 and 23A/23B, using the designated custom-license mechanism and any required CGTrader written confirmation. Until then no model files will be downloaded or ingested, and no derived geometry will be published.

No sellers were contacted; no purchase, account, credential or access-control actions were taken. No build, lint, formatter or test suite was run for this research assignment.