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Etsy Storefront Publishing & Sourcing Guide

This operations guide provides a complete, step-by-step walkthrough for launching and managing the StackCalc Etsy Storefront, accompanied by the strategic manufacturing assessment for Batch 001 In-House Printing vs. Slant3D Additive Sourcing.

1. Sourcing Strategy: In-House Printing vs. Slant3D for Batch 001

Strategic Recommendation: The "In-House Pilot → Slant3D Farm Scale" Hybrid Model

Executive Summary:
Print Batch 001 (5 units per SKU: 1 studio master copy + 4 ready-to-ship boxed copies) IN-HOUSE.
Do not outsource Batch 001 completely to Slant3D. Maintain full in-house control over the inaugural release, then transition high-volume, single-material components to Slant3D once sales velocity is established.

                    BATCH 001 (LAUNCH & PILOT)             BATCH 002+ (SCALE)
┌──────────────────┐  In-House High-Precision Printing      In-House Assembly & QA
│ SC-32 Calculator │ ─────────────────────────────────► ─────────────────────────────►
│ (Dovetail + TPU) │  • 0.15mm TPU membrane (Azure)         • Pre-soldered SMT PCB
│                  │  • Archimedean micro-groove faceplate  • Multi-material faceplates
└──────────────────┘  • 0.20mm sliding rail calibration    • Final serialized testing

┌──────────────────┐  In-House Textured PEI Pilot           Slant3D Additive Farm
│ Math             │ ─────────────────────────────────► ─────────────────────────────►
│ Manipulatives    │  • 10-20 units per SKU                 • High-volume PLA printing
│ (Fraction, Clock)│  • Zero MOQ, zero lead time wait       • Automated fulfillment
└──────────────────┘  • Immediate OpenSCAD CAD tuning       • Monolithic trays & blocks

Detailed Engineering & Economic Comparison

Strategic Dimension In-House 3D Printing (Batch 001) Direct Slant3D Sourcing (Batch 001) Winner for Batch 001
Mechanical Tolerances High Precision (\(0.20\,\text{mm}\) dovetails): Calibrated on tuned Bambu/Prusa machines. Tool-free sliding rails glide smoothly without binding or slop. Standard Industrial (\(0.40–0.60\,\text{mm}\)): Slant3D uses high-flow production nozzles; tight sliding tongue-and-groove joints can bind or require manual post-cleanup. In-House
Multi-Material / CMF Full CMF Capability: Can print Shore 95A flexible TPU membranes, anisotropic silk PLAs, frosted optical PETG, and Archimedean spiral concentric toolpaths. Single-Material PLA/PETG: Slant3D farm lines do not support multi-material TPU co-molding, special silk gradients, or laser foil inlays. In-House
Inventory & Cash Risk Zero Upfront Inventory: Print on-demand or keep 5–10 kits boxed on the shelf. Zero capital tied up in unsold units. Batch MOQ / Setup Overhead: Outsourcing small test runs incurs setup fees, shipping freight, and MOQ constraints. In-House
Rapid Iteration Cycle Immediate (10 minutes): If an early customer reports a fraction block or algebra tile is 0.1mm too snug, you modify the OpenSCAD code and print the corrected part immediately. Slow (2–4 weeks): Re-uploading CAD, queueing at the farm, batch fabrication, and ground freight back to your shop. In-House
First Review Reputation Boutique Surface Finish: Textured PEI plates, dialed retraction (\(0.98\) flow), and hand-checked snap retention generate enthusiastic 5-star Etsy reviews. Factory Finish: Quality is consistent for volume parts, but lacks the hand-inspected artisan feel needed for early Listing Quality Score (LQS). In-House
High-Volume Unit Cost Higher labor cost per unit if scaled past 100 units/month. Lowest Cost at Scale: Robotic automated ejection and bulk filament pricing dominate at \(>100\) units. Slant3D (Scale)

When to Trigger the Slant3D Hand-Off (Batch 002+ Milestone)

Transition parts to Slant3D when: 1. Steady Velocity: A manipulative SKU sells \(>20\) units per month, or a school district places a PO for \(>10\) classroom kits (\(>150\) total trays/boxes). 2. Stable Geometry: The OpenSCAD CAD code has zero geometry adjustments across 30 days of classroom feedback. 3. Component Suitability: Outsource the monolithic, high-part-count components (e.g. Fraction Studio towers, Gridfinity boxes, Ten-Frame carry shelves) while continuing to assemble, QA, and package in-house with the SC-32 electronics.

2. Pre-Publishing Master Directory & Asset Index

All 8 launch listings have complete, pre-validated copy-paste Markdown packages located in the repository at watch-calc-32/documentation/etsy/. Master images are generated in high-resolution \(2000 \times 2000\) (1:1 Square) and \(2000 \times 1500\) (4:3 Horizontal) in stackcalc/docs/assets/renders/etsy/.

Master Listing Catalog

SKU Product Listing Guide Base Price Primary 1:1 Image Asset 4:3 Context Banner Asset
SC-32-HW SC-32 Scientific RPN Maker Kit $89.00 sc32-hero-keynote-square.png sc32-hero-keynote-4x3.png
FRAC-01 Fraction Studio Towers $48.00 fraction-studio-hero-square.png fraction-studio-hero-4x3.png
PRIME-01 Prime Factor Studio & Slide Rule $46.00 prime-studio-hero.png prime-studio-hero.png
TILE-01 Counting Tiles & Planar Array Studio $44.00 counting-tiles-hero.png counting-tiles-hero.png
TIME-01 Classroom Planetary Clock $44.00 clock-classroom-hero-square.png clock-classroom-hero-4x3.png
ALGB-01 Algebra Factoring Studio $42.00 algebra-boxes-hero-square.png algebra-boxes-hero-4x3.png
DOMI-01 Math Domino Studio $38.00 dominoes-studio-hero-square.png dominoes-studio-hero-4x3.png
BASE-10 Ten-Frames & Counters $36.00 ten-frames-hero-square.png ten-frames-hero-4x3.png
PROB-01 Probability Dice & Spinner $36.00 dice-spinner-hero-square.png dice-spinner-hero-4x3.png
TRIG-01 Unit Circle Trig Volvelle $19.00 unit-circle-volvelle-hero-square.png unit-circle-volvelle-hero-4x3.png
DIGI-01 Complete 3D Print STL Library $19.00 algebra-tiles-craftsmanship-square.png algebra-boxes-hero-4x3.png
REPLACE-01 Lifetime Replacement Parts Service $2.49+ infographic-guarantee-safety-square.png infographic-guarantee-safety-square.png

3. Step-by-Step Publishing Guide (Etsy Shop Manager)

Follow this exact 9-step procedure for every product listing to maximize conversion rate and guarantee compliance with Etsy's 2026 search ranking algorithms.

Step 1: Photos & Video Upload (10/10 Slots Filled)

  1. Open Etsy Shop Manager → Listings → Add a listing.
  2. Drag and drop all 10 image assets from watch-calc-32/documentation/etsy/images/ according to the carousel order specified in each listing's Markdown file:
  3. Slot 1 (Primary Thumbnail): *-hero-square.png (Crisp 1:1 square render on clean studio background).
  4. Slot 2 (Context Banner): *-hero-4x3.png (Wide contextual angle showing desk integration).
  5. Slots 3–6 (Features & Craftsmanship): Close-up macro shots of tactile surfaces, debossed text, and modular dovetails.
  6. Slot 7 (Technical Specs Infographic): Pre-generated blueprint infographic showing dimensions, grades, and parts.
  7. Slot 8 (Ecosystem): Docking onto standard 42mm Gridfinity desktop trays.
  8. Slot 9 (Accessories): Reconfigurable desk stand or protective TPU sleeve.
  9. Slot 10 (Safety & Trust Infographic): Lifetime piece guarantee, non-toxic material badge, CPSIA notice.
  10. Upload Product Video: Drag and drop the corresponding MP4 video from stackcalc/docs/assets/videos/ (5–15 second silent 1080p demonstration).
  11. Fill In Image Alt Text: Click each image thumbnail in Etsy and paste the exact pre-written descriptive Alt Text provided in Section 3 of the listing markdown file (essential for Google Image Search and accessibility).

Step 2: Listing Title & Category Placement

  1. Title: Copy the front-loaded title from Section 1 of the product markdown file.
  2. Example: RPN Scientific Calculator - StackCalc SC-32 Open Hardware RP2350 Tactile Keypad Pocket Calculator for STEM & Exam Use
  3. Why: The first 40 characters contain the primary keywords (RPN Scientific Calculator - StackCalc SC-32) to prevent truncation on mobile screens.
  4. Category Selection:
  5. For SC-32: Home & Living > Office > Office Supplies > Calculators
  6. For Manipulatives: Toys & Games > Learning & School > Math Toys (or Office Supplies > Desk Organizers)

Step 3: Product Attributes & Search Facets

Select all relevant attributes in Etsy Shop Manager to ensure your item appears when shoppers filter search results: - Primary Color / Finish: (e.g. Black for Stealth, White for Retrofuturism, Blue for Voyager). - Primary Material: Plastic (or Bioplastic / PLA). - Subject: Mathematics, Engineering & Technology, Computer Science. - Target Age / Grade: Select matching grade range (Kindergarten–3rd for Ten-Frames, Grade 3–8 for Fractions, High School/College for SC-32 & Algebra).

Step 4: Product Description & Safety Statements

  1. Copy the full formatted description from Section 4 of the listing markdown file.
  2. Verify that the Mandatory Safety Disclaimer is intact: 
    WARNING: CHOKING HAZARD – Small parts.
Not for children under 3 years. Recommended for ages 6+ under adult supervision.
  3. Highlight the "No Lost Piece Left Behind" Lifetime Guarantee:

    "Classrooms lose pieces. If a student loses any fraction block, algebra tile, or counter, we provide exact matching replacement parts starting at $2.49 for the lifetime of the product, matched to the Part ID on your included Archival Reference Card."

Step 5: Production Partner Declaration

Etsy requires makers to disclose production assistance under their Creativity Standards: 1. Scroll to Production Partners. 2. Select your registered production partner profile: - For Batch 001 (In-House): Check "I make this item myself" (StackCalc California Studio). - For Batch 002+ (Slant3D): Select Slant 3D (Boise, Idaho) with the note: "Custom 3D CAD design, circuit schematic, firmware, and quality control performed in-house; contract farm printing by Slant 3D."

Step 6: 13/13 Search Tag Saturation

Copy all 13 exact-match tags from Section 2 of the listing file. Enter each tag individually (all under 20 characters): - Example for SC-32: rpn calculator, pocket calculator, stem calculator, math engineering, scientific tool, coder desk toy, engineer gift, sat test calculator, rp2350 hardware, retro calculator, tactile keyboard, college math tool, physics calculator. - Rule: Use all 13 tags. Never leave empty tag slots.

Step 7: Dropdown Variations (CRO Booster)

Enable Variations in the listing editor to provide tier options that increase Average Order Value (AOV): - Option 1 (Maker Kit / Base Unit): 100% pre-soldered RP2350 logic board, tool-free 5-min snap assembly ($89.00). - Option 2 (Classroom Station 5-Pack): 5 pre-soldered Maker Kits + bulk teacher lesson guide with standard volume tiering.

Step 8: Standardized Shipping Profile Selection

Select the pre-configured USPS Ground Advantage shipping profile: - Profile A (Small Manipulative - 5.1 oz): $4.49 (or Free on orders $35+). - Profile B (Learning Box - 10.9 oz): $5.49 (or Free on orders $35+). - Profile C (SC-32 Calculator - 12.7 oz): $5.99 (or Free on orders $35+). - Profile E (Replacement Envelope - 1.2 oz): Included in base refill tier. - Processing Time: Set to 1–3 business days (or 24 hours for refills).

[!TIP] For complete dimensional box engineering, duplex \(135 \times 90\,\text{mm}\) reference card workflows (high-speed laser paper vs. monochrome laser engraving), and the 6-step bench packing protocol, see the Shipping, Packaging & Fulfillment Protocol.

Step 9: Publish & Initial Ranking Boost

  1. Click Publish (listing fee: $0.20 USD).
  2. Initial Social Proof: Send the listing URL to your pilot educator mailing list. Etsy heavily weights initial click-through rate (CTR) and conversion velocity in its first 72 hours.
  3. Link the Etsy listing URL directly into the official documentation and master catalog at stackcalc.io/products/.

4. Git Hash Tracking & 50% Anti-Arbitrage Replacement Workflow

4.1 The 50% Anti-Arbitrage Pricing Formula

To prevent customers or third parties from buying individual components to assemble full kits piecemeal, all replacement parts are priced at 50% above the amortized per-piece price of the full retail kit (\(1.5 \times \text{Amortized Cost}\)): - Small Tile / Counter / Single Domino Tile: $2.49 (Amortized $1.66) - Trio Small Tiles / Domino 6-Pack: $3.99 – $6.75 (Amortized $2.66–$4.50) - Linear Rod / Medium Tower: $3.49 – $4.95 (Amortized $2.33–$3.30) - Quadrant Wedge / Clock Hand: $5.25 – $6.00 (Amortized $3.50–$4.00) - 12-Frame Math Tray / Doubling Lid / Quadratic x² Tile: $6.49 – $7.50 (Amortized $4.33–$5.00) - Whole Block / 3x1x7U Storage Box / Complete Stand: $11.25 – $22.50 (Amortized $7.50–$15.00) - Planetary Gear Core / SC-32 Bezel: $18.00 – $24.00 (Amortized $12.00–$16.00)

Anti-Arbitrage Result: Assembling an entire kit piecemeal costs \(>2.2\times\) the boxed retail price, eliminating part-out arbitrage while keeping single-piece replacement affordable for honest classrooms.

4.2 Automated Git Content-Addressed Manifest Tracking (Zero Version Churn)

A common concern with Git-based versioning is: "Does every commit to the repository bump the version of all physical parts?"
No. We eliminate global version churn by leveraging Git's fundamental content-addressing architecture:

  1. Git Content Blob Hashes (git hash-object):
  2. The primary ID for every STL model is its Git Blob SHA (e.g., 0bf1e7f for algebra_factoring_box.stl).
  3. This SHA is computed strictly from the uncompressed byte content of the 3D geometry file (SHA-1("blob " + size + "\0" + bytes)).

  4. Invariance Guarantee: Whether you make 1 commit or 10,000 commits to documentation, website pages, or Swift calculator code, the Git Blob Hash for that physical part never changes. It is 100% frozen in time until someone actually alters that specific CAD model.

  5. Path-Scoped CAD Commits (git log -1 -- <file>):

  6. When referencing authoring Git commits, the tooling queries the exact file: git log -1 --format="%h" -- Education/scad/fraction_studio_box.scad.

  7. Commits elsewhere in the monorepo do not alter this commit stamp. It only advances when that component's CAD code is modified.

  8. Part Identification Syntax:

  9. Standard Part ID format: <KIT_CODE>-<COMPONENT_SLUG>-<BLOB_SHA> (e.g., FRAC-FRAC-eba4c3e, SC-CHAS-436ba32).
  10. Customers can quote either the full Part ID, the debossed 7-character Git Blob Hash (eba4c3e), or the CAD commit (a793ddd).
  11. Automated Manifest Tool (Tools/generate_part_manifest.py): 
    # Regenerate the master part manifest and anti-arbitrage pricing:
python3 Tools/generate_part_manifest.py

# Reverse lookup any customer Git Blob Hash, commit, or component:
python3 Tools/generate_part_manifest.py --lookup eba4c3e
    The lookup instantly prints the component name, exact immutable Git blob SHA, CAD source commit, amortized cost, 50% anti-arbitrage price, and exact Git export command (git cat-file -p <blob_sha> > component.stl).

4.3 The Etsy Replacement Parts Workflow

  1. Customer Order: A customer who lost a piece visits our dedicated Etsy listing (SC-REPLACE-01).
  2. Personalization Box: The buyer provides 3 details:
  3. Target Set (e.g. Fraction Studio, Algebra Factoring, SC-32)
  4. Missing Part & Color (e.g. 1/8 Eighth Block in Azure Blue, Linear x Rod in Coral)
  5. Part ID or Git Hash: Matched directly from the Archival Reference Card included inside their kit's box lid (or the underside inspection plaque on the box/chassis, e.g. FRAC-01-eba4c3e or a793ddd).
  6. Automated CAD Slicing: The fulfillment technician runs python3 Tools/generate_part_manifest.py --lookup <ID>, checks out the exact historical OpenSCAD commit, and slices on textured PEI.
  7. 24-Hour Dispatch: The replacement part is dispatched in a rigid stay-flat mailer envelope via standard USPS First Class mail with flat tracking.

5. Battery-Free Shipping Compliance Policy

[!IMPORTANT] Strict Postal Compliance: NO BATTERIES SHIPPED IN ANY PACKAGE.
In compliance with USPS Publication 52 (Hazardous Materials), FAA safety regulations, and IATA Class 9 (UN 3090 / UN 3091) air transport restrictions, StackCalc does not include lithium coin cell batteries in physical calculator shipments.

Operational Rationale & Benefits:

  1. Zero Hazmat Labeling & Airmail Friction: Lithium cells trigger complex DOT/USPS Section 349 shipping rules, hazardous materials declarations, package labeling mandates, and restrictions on international priority airmail.
  2. Eliminated Fire & Ingestion Liability: Eliminates Reese's Law (16 CFR Part 1263) pre-installed battery testing certification requirements for shipping packages.
  3. Universal Accessibility: The SC-32 uses a standard, ubiquitous CR2032 3V coin cell available at any grocery store, pharmacy, or hardware store for ~$0.50.
  4. Transparent Customer Notice: Every calculator listing and package insert clearly states:
    "Requires 1x standard CR2032 coin cell (widely available, omitted from shipment per postal carrier safety regulations)."

6. Comprehensive Item-by-Item Packing Checklists

Before sealing each mailer, warehouse fulfillment must execute the specific checklist for the SKU being dispatched. All boxed kits must include their dedicated Archival Reference & Schematic Card to serve as the master inventory, schematic diagram, and lifetime replacement ledger:

[!TIP] Packing Bench Web Tool: Open docs/downloads/packing_bench_cards.html on any desktop or tablet for instant 1-click printable packing bench sheets with full CAD schematics and Part ID verification checkmarks.

1. SC-32 Scientific RPN Calculator (Standard Hardware Kit)

  • Packaging: Profile C Mailer (\(9 \times 6 \times 3\text{ in}\) Rigid Corrugated Mailer Box)
  • Target Weight: ~360 g (12.7 oz) packed
  • Physical Contents:
  • [ ] 1x Pre-Soldered SC-32 Maker Kit (pre-soldered RP2350 SMT mainboard, tool-free sliding chassis shell, top cap, tactile membrane, faceplate)
  • [ ] 4-Piece Interlocking Puzzle Stand (seated as internal packaging trusses or flat nested)
  • [ ] NO BATTERY VERIFICATION: Confirmed battery compartment is completely empty (no CR2032 cell inside per postal rules).
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (SC-32-HW, with exploded assembly, puzzle stand diagram, Part IDs, and specs)
  • [ ] 1x Double-Sided Credit Card RPN Reference Guide (reference_card_front.svg / reference_card_back.svg)
  • [ ] 1x Power & Safety Slip: "Requires 1x CR2032 coin cell (battery omitted per USPS/ICAO air safety)"
  • Pre-Sealing QA Gate:
  • [ ] Sliding faceplate dovetail glide test (smooth engagement, no binding)
  • [ ] All 43 tactile snap-domes actuate cleanly with distinct audible snap
  • [ ] ST7567A transflective LCD bezel centered in cowl aperture
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on chassis bottom

2. SC-32 Engineer's Field Pack / Founder Edition

  • Packaging: Profile C Mailer (\(9 \times 6 \times 3\text{ in}\) Rigid Corrugated Mailer Box)
  • Target Weight: ~420 g (14.8 oz) packed
  • Physical Contents:
  • [ ] 1x Pre-Soldered SC-32 Maker Kit
  • [ ] 4-Piece Interlocking Puzzle Stand
  • [ ] 1x Reversible Shore 95A Flexible TPU Protective Cozy Pouch
  • [ ] 1x Founder's Serialized Rear Nameplate (inspected for crisp Space Mono laser engraving)
  • [ ] NO BATTERY VERIFICATION: Confirmed battery compartment is empty.
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (SC-32-HW)
  • [ ] 1x Double-Sided Credit Card Reference Guide
  • [ ] 1x Founder's Welcome Letter & Quick-Start Slip
  • [ ] 1x Battery Postal Safety & Lifetime Guarantee Postcard

3. SC-6 Elementary RPN Calculator

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~290 g (10.2 oz) packed
  • Physical Contents:
  • [ ] 1x SC-6 Elementary Calculator (Impact-resistant Elegoo Space Gray / Midnight Navy PLA 2.0+ chassis, Slate Gray sliding cowl, tactile snap-dome keypad)
  • [ ] 1x 2-Piece Folding Desk Wedge Stand
  • [ ] NO BATTERY VERIFICATION: Confirmed battery cavity is empty.
  • Printed Collateral & Cards:
  • [ ] 1x SC-6 Elementary Student Quick-Start Card (sc6_guide_card.png)
  • [ ] 1x Parental Power Notice: "Requires 1x standard CR2032 coin cell (battery omitted per postal rules)"
  • [ ] 1x Safety & Choking Hazard card (Ages 6+) + Lifetime Warranty card

4. Fraction Studio Proportional Towers (Full Classroom Kit)

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~310 g (10.9 oz) packed
  • Physical Contents:
  • [ ] 15x Debossed 4-Face Proportional Blocks (100% clean math blocks, free of technical alphanumeric codes):
    • [ ] 1x Whole Block (1.0 / 100% / 360°)
    • [ ] 2x Half Blocks (1/2 / 0.50 / 50% / 180°)
    • [ ] 4x Quarter Blocks (1/4 / 0.25 / 25% / 90°)
    • [ ] 8x Eighth Blocks (1/8 / 0.125 / 12.5% / 45°)
  • [ ] 1x 42mm Gridfinity Storage Tray with sliding locking lid
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (FRAC-01, with exploded isometric schematic, Part IDs FRAC-01-eba4c3e, piece counts, and replacement instructions)
  • [ ] 1x Fraction Equivalence Pocket Reference Guide (card_fractions-pocket-guide.svg)
  • [ ] 1x CPSIA Choking Hazard Card (Ages 6+ notice for eighth blocks)
  • Pre-Sealing QA Gate:
  • [ ] Blocks stand flush on tabletop without tipping; debossed notation is crisp and legible
  • [ ] Clean Manipulatives Check: Student blocks verified 100% free of distracting technical hashes
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on storage box lid underside

5. Algebra Factoring Studio & Polynomial Tiles

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~340 g (12.0 oz) packed
  • Physical Contents:
  • [ ] 1x Dual-L Factoring Stage with perimeter slotted factoring rails
  • [ ] 38x Chamfered Polynomial Tiles (100% clean math tiles with \(+x^2/-x^2\) badges only, zero technical hashes):
    • [ ] 4x \(x^2\) Large Quadratic Tiles (dual-color / debossed)
    • [ ] 10x \(x\) Linear Rectangle Tiles
    • [ ] 24x \(1\) Unit Constant Square Tiles
  • [ ] 1x 42mm Gridfinity 3x1 Storage Box with debossed lid
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (ALGB-01, with factoring stage schematic, Part IDs ALGB-01-a793ddd, piece counts, and QC checkmarks)
  • [ ] 1x Binomial Factoring Quick Reference Guide (algebra_tiles-pocket-guide.svg)
  • [ ] 1x Safety Card (Small parts: unit tiles)
  • Pre-Sealing QA Gate:
  • [ ] Tiles seat smoothly into the L-frame stage rails without catching
  • [ ] Clean Manipulatives Check: Student tiles verified 100% free of technical alphanumeric codes
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on storage box base

6. Sectional Classroom Planetary Clock

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~320 g (11.3 oz) packed
  • Physical Contents:
  • [ ] 1x Synchronized 12:1 Internal Planetary Gear Core
  • [ ] 1x Hour Hand + 1x Minute Hand (pre-synchronized to 12:00)
  • [ ] 4x Removable 5-Minute Quadrant Wedges (:15, :30, :45, :00)
  • [ ] 1x 42mm Gridfinity 2x1 Desktop Showcase Stand
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (TIME-01, with exploded planetary gear schematic, Part IDs TIME-01-xxxxxxx, and ratio specs)
  • [ ] 1x Clock Mechanics & Elapsed Time Student Activity Guide (clock_quadrants-pocket-guide.svg)
  • [ ] 1x Safety & Replacement Service Card
  • Pre-Sealing QA Gate:
  • [ ] Hands rotate smoothly 360° with positive 12:1 gear engagement; quadrants seat securely
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on stand base

7. Dual Ten-Frames & Carry Shelf Set

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~280 g (9.9 oz) packed
  • Physical Contents:
  • [ ] 2x 2x5 Ten-Frame Grid Stages
  • [ ] 1x Elevated Regrouping Carry Shelf with dock latch
  • [ ] 20x Bi-Color Tactile Counting Counters (100% clean manipulatives, zero technical codes)
  • [ ] 1x 42mm Gridfinity 3x1 Storage Caddy
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (BASE-10, with stage schematics, Part IDs BASE-10-xxxxxxx, and QC checkmarks)
  • [ ] 1x Base-Ten Regrouping & Make-a-Ten Lesson Card (ten_frame_tray-pocket-guide.svg)
  • [ ] 1x CPSIA Choking Hazard Card (Ages 6+ notice for counters)
  • Pre-Sealing QA Gate:
  • [ ] Counter cavities hold counters securely; carry shelf docks firmly into dual frames
  • [ ] Clean Manipulatives Check: Student counters verified free of technical markings
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on caddy base

8. Probability Dice & Modular Spinner Pack

  • Packaging: Profile A Mailer (\(7 \times 5 \times 2\text{ in}\) Crush-Proof Mailer Box)
  • Target Weight: ~190 g (6.7 oz) packed
  • Physical Contents:
  • [ ] 1x Ultra-Low-Friction Centered Probability Spinner Base
  • [ ] 4x Interchangeable Sector Discs (4, 6, 8, and 12 sectors)
  • [ ] 5x Mathematical Polyhedral Dice (D4, D6, D8, D10, D12)
  • [ ] 1x 42mm Gridfinity 1x1 Storage Box with magnetic/friction lid
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (PROB-01, with disc exploded diagram and Part IDs)
  • [ ] 1x Theoretical vs. Experimental Probability Pocket Guide (dice_pack-pocket-guide.svg)
  • [ ] 1x Safety (Dice choking hazard) Card
  • Pre-Sealing QA Gate:
  • [ ] Spinner rotates freely for \(>8\) seconds on a single flick without axial wobble
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on box base

9. Unit Circle Trigonometry Volvelle

  • Packaging: Profile A Mailer or Rigid Cardboard Flat Mailer (\(7 \times 5\text{ in}\))
  • Target Weight: ~95 g (3.4 oz) packed
  • Physical Contents:
  • [ ] 1x Dual-Disc Rotating Volvelle (Stator + Rotor connected via flush eyelet rivet)
  • [ ] Laser-engraved / high-contrast printed degree, radian, \((\cos\theta, \sin\theta)\), and \(\tan\theta\) scales
  • [ ] 1x Rigid Protective Stiffener Cardboard Backer
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (VOLV-01, with angle callouts and Part IDs)
  • [ ] 1x Trig Identities & Pythagorean Unit Circle Cheatsheet
  • Pre-Sealing QA Gate:
  • [ ] Smooth 360° disc rotation; radial viewing windows align precisely with coordinate pairs

10. 3-in-1 Reconfigurable Stand & TPU Pouch Pack

  • Packaging: Profile A Mailer (\(7 \times 5 \times 2\text{ in}\) Crush-Proof Mailer Box)
  • Target Weight: ~160 g (5.6 oz) packed
  • Physical Contents:
  • [ ] 4x Interlocking Puzzle Stand Pieces (piece_c_bl, piece_c_br, piece_c_tl, piece_c_tr)
  • [ ] 2x Stand Rail Connectors (piece_stand_front, piece_stand_rear)
  • [ ] 1x Reversible Shore 95A Flexible TPU Travel Sleeve (dockable in 3-ring binder)
  • Printed Collateral & Cards:
  • [ ] 1x Dual Incline Stand Assembly Diagram (\(78^\circ\) upright vs. \(10^\circ\) typing wedge)
  • [ ] 1x Lifetime Guarantee Card

11. Concrete Math Challenge Deck (60 Challenge Cards)

  • Packaging: Profile A Mailer (\(7 \times 5 \times 2\text{ in}\) Crush-Proof Mailer Box)
  • Target Weight: ~220 g (7.8 oz) packed
  • Physical Contents:
  • [ ] 60x Heavyweight Plastic-Coated Challenge Cards (\(350\,\text{gsm}\) linen finish, rounded corners)
  • [ ] 1x Rigid 2-Piece Telescoping Storage Box with thumb notches
  • Printed Collateral & Cards:
  • [ ] 1x CCSS Mathematical Practices & Answer Key Booklet
  • [ ] 1x Classroom Replacement Guarantee Card

12. Complete 3D Print STL Library (Digital Download)

  • Packaging: Automated Instant Digital Delivery (.ZIP)
  • Target Weight: 0 g (Digital Delivery)
  • Digital Contents:
  • [ ] Complete verified STLs for all 8 physical manipulative kits and SC-32 mechanical prototype
  • [ ] 3MF Reference Print Projects with pre-tuned slicer speeds, support-free orientations, and infills
  • [ ] 1x Comprehensive Print Orientation & Slicing PDF Field Manual

13. Replacement Parts Service Envelope (SKU: REPLACE-01)

  • Packaging: Profile E Mailer (\(6 \times 4.5\text{ in}\) Rigid Stay-Flat Cardboard Mailer Envelope)
  • Target Weight: ~35 g (1.2 oz) packed
  • Physical Contents:
  • [ ] 1x 3D Printed Replacement Component (verified against order personalization notes)
  • [ ] Revision tolerance check (matched to customer's stated REV code)
  • Printed Collateral & Cards:
  • [ ] 1x Thank-You Slip: "Thanks for keeping your StackCalc kit in action! Need more parts? stackcalc.io"
  • Pre-Sealing QA Gate:
  • [ ] Debossed notation is sharp and legible; perimeter chamfers are smooth

14. Math Domino Studio & 12-Frame Tray Set (SKU: DOMI-01)

  • Packaging: Profile B Mailer (\(8 \times 6 \times 3\text{ in}\) Heavyweight Mailer Box)
  • Target Weight: ~320 g (11.3 oz) packed
  • Physical Contents:
  • [ ] 30x Math Dominoes (28 standard double-six [0|0 through 6|6] + 2 blank wildcards [B|B]) with debossed pips and central divider
  • [ ] 1x 12-Frame Ten-Frame Math Tray (10-frame baseline + 2-frame overflow dock)
  • [ ] 1x Doubling Snap Lid with debossed reference scale and snap detents
  • [ ] 1x 42mm Gridfinity 3x1x7U Storage Box with debossed lid and inspection plaque
  • Printed Collateral & Cards:
  • [ ] 1x Archival Reference & Schematic Card (DOMI-01, with exploded isometric schematic, Part IDs DOMI-01-xxxxxxx, 30-tile inventory, and replacement instructions)
  • [ ] 1x Math Domino Subitizing & Arithmetic Pocket Guide (dominoes-pocket-guide.svg)
  • [ ] 1x Safety Card (Small parts warning: Ages 6+)
  • Pre-Sealing QA Gate:
  • [ ] Tiles slide smoothly into tray slots and stack neatly inside 3x1x7U storage box
  • [ ] Debossed pips are sharp, distinct, and clean of flash
  • [ ] Doubling lid snaps securely onto tray with audible tactile snap
  • [ ] Underside inspection plaque verified: Mirrored Space Mono Bold deboss on storage box base

7. Maintenance & Image Re-Generation Pipeline

If CAD models or colorway finishes change in the future, regenerate all cropped Etsy square and 4:3 assets automatically using the repository Makefile:

# Navigate to watch-calc-32 repository
cd /Users/abagher/Documents/GitHub/watch-calc-32

# Re-crop all master renders into Etsy 1:1 Square (2000x2000) and 4:3 (2000x1500)
make crop-images

# Full rebuild of OpenSCAD models, raytraced stills, and Etsy crops:
make images

All generated files will update synchronously in both documentation/etsy/images/ and stackcalc/docs/assets/renders/etsy/.

8. Multi-Marketplace Visual Asset Strategy & Blender Physics Pipeline

StackCalc products are syndicated across Etsy, Amazon Handmade, eBay, and our direct website (stackcalc.io). Each channel requires distinct visual asset standards:

1. Amazon Main Image Compliance Standard (Pure White #FFFFFF)

  • TOS Requirement: Amazon Seller Central and Handmade policies require MAIN listing images to feature a 100% pure white background (RGB 255, 255, 255 / #FFFFFF). Images with off-white backgrounds, props, or text overlays are algorithmically suppressed.
  • Implementation (setup_amazon_white_background):
  • World background set to (1.0, 1.0, 1.0, 1.0).
  • Floor plane set as Cycles is_shadow_catcher = True to preserve soft, natural contact ambient occlusion shadows without dirtying the white level.
  • Product occupies 85–90% of the frame with zero graphic text overlays.

2. 3D-Modeled Environments (Strictly NO AI Generation)

  • Why AI Images are Rejected: Generative AI tools (Midjourney/Flux/Photoshop) hallucinate geometry, scramble debossed mathematical notation, create impossible gear tooth profiles, and trigger deep skepticism among discerning STEM teachers and engineers.
  • The 3D PBR Environment Standard: All contextual lifestyle scenes are rendered directly in Blender Cycles using our authentic OpenSCAD CAD models resting inside photorealistic 3D-modeled environments:
  • Procedural Scandinavian blonde and honey oak desk surfaces (create_smooth_oak_desk_material).
  • Physical drafting tools (aluminum millimeter rulers, self-healing cutting mats).
  • Subtle depth-of-field (f/3.2 camera aperture) softly blurring classroom background elements while keeping CAD chamfers razor-sharp.

3. Bullet Physics Simulation Mandate (Zero Intersecting Boxes)

  • Problem: Hardcoded static coordinates often result in loose blocks or tiles penetrating tray sidewalls or clipping through box lips.
  • Mandate: All multi-object Blender scenes must invoke simulate_rigid_body_settling(scene, passive_objs, active_objs):
  • Containers (Gridfinity boxes, calculation stages, desk surfaces) are configured as PASSIVE rigid bodies with MESH collision shapes.
  • Loose components (polynomial tiles, fraction blocks, counters, dice) are configured as ACTIVE rigid bodies with CONVEX_HULL shapes.
  • The physics engine steps 35 frames under standard gravity (\(g = -9810\,\text{mm/s}^2\)) with dampening until equilibrium is reached.
  • Visual transforms are permanently baked (matrix_world.copy()) prior to Cycles rendering, guaranteeing physically valid, non-intersecting geometry.

9. Real Physical Product Photography & Digital Darkroom Pipeline

While CAD raytracing and physics settling provide ideal architectural consistency, real physical photographs of authentic 3D printed parts dramatically outperform synthetic images in conversion rate (CRO). Savvy Etsy shoppers, STEM teachers, and school procurement officers actively look for real physical surface textures, genuine matte PEI bed patterns, authentic layer adhesion, and debossed inspection marks.

9.1 The "Zero AI Hallucination" Standard

  • Strict Prohibition: Never use text-to-image generative AI (e.g. Midjourney, Flux, Imagen) to create commercial hero shots. Generative AI hallucinates impossible geometry, distorts debossed typography, and erodes customer trust.
  • The Physical Digital Darkroom: All commercial studio shots must be generated directly from authentic, bench-photographed hardware using computer vision and digital darkroom processing (Tools/rendering/enhance_real_photos.py).

9.2 The 5-Stage Retouching & Staging Workflow

┌─────────────────────────┐     1. D65 White Balance       ┌─────────────────────────┐
│ Raw Bench Photograph    │ ────────────────────────────► │ Neutral Color Temp      │
│ (Yellow Tungsten Cast)  │     (Gray-world algorithm)     │ (Maple/PEI Restored)    │
└─────────────────────────┘                                └────────────┬────────────┘
                                                                        │
                                2. CLAHE Luminance Micro-Contrast       ▼
                                ────────────────────────────────► ┌─────────────────────────┐
                                (Highlights debossed letters &    │ Matte Texture Pop       │
                                 fuzzy-skin tactile ridges)       │ (Clean Dark Charcoal)   │
                                                                  └────────────┬────────────┘
                                                                               │
                                3. GrabCut Foreground Extraction               ▼
                                ────────────────────────────────► ┌─────────────────────────┐
                                (Feathered sub-pixel alpha mask)  │ Isolated Real Box       │
                                                                  └──────┬───────────┬──────┘
                                                                         │           │
                     4A. Ground Contact Shadow Projection                │           │ 4B. Desk Staging
       ┌─────────────────────────────────────────────────────────────────┘           │
       ▼                                                                             ▼
┌─────────────────────────────────┐                       ┌─────────────────────────────────┐
│ Pure White (#FFFFFF) Studio     │                       │ Classroom Desk In-Situ          │
│ • Amazon/eBay/Etsy main shot    │                       │ • Textured wooden study desk    │
│ • Multi-stage contact AO shadow │                       │ • Soft f/2.8 background bokeh   │
│ • Razor-sharp physical print    │                       │ • Natural warm wood reflections │
└─────────────────────────────────┘                       └─────────────────────────────────┘
  1. D65 Daylight Normalization: Corrects the typical indoor warm tungsten or fluorescent color cast back to neutral daylight (6500K), ensuring accurate plastic and desk color representation.
  2. Micro-Contrast & Texture Extraction: Applies Contrast Limited Adaptive Histogram Equalization (CLAHE) on the LAB luminance channel (\(L^*\)) to elevate subtle debossed lettering (TEN FRAMES, StackCalc), layer lines, and fuzzy-skin matte textures without washing out contrast.
  3. Sub-Pixel Alpha Segmentation: Uses OpenCV GrabCut with elliptical morphological closing and Gaussian edge feathering to isolate the real 3D printed box without stray halos or burrs.
  4. Physically Grounded Contact Shadows: Eliminates "floating box" artifacts by extracting the real ground contact polygon (\([x_{min}, y_{contact}]\) to \([x_{max}, y_{contact}]\)) and rendering a multi-stage ambient occlusion shadow (tight dark contact line + soft diffused floor penumbra).
  5. Multi-Marketplace Compositing:
  6. Amazon / eBay / Etsy Main Image: Scaled and centered with 12–15% breathing room on pure white (#FFFFFF).
  7. Contextual In-Situ Image: Composited onto high-resolution 3D-modeled classroom oak desks with optical depth-of-field blur.
  8. Retouched Bench Hero: Full-resolution original workshop photo with professional lighting, contrast curve, and lens vignette.

9.3 Deployed Real Photo Asset Index (SKU: BASE-10)

All assets are generated in both 1:1 Square (\(1600 \times 1600\,\text{px}\)) and 4:3 Horizontal (\(1600 \times 1200\,\text{px}\)) in both Clean and Badged editions:

Asset Name Format Staging Environment Primary Marketplace Channel
ten-frames-real-front-white-square.png 1:1 Square Pure White #FFFFFF Amazon Main, eBay Main, Etsy Slot 1
ten-frames-real-angle-white-square.png 1:1 Square Pure White #FFFFFF Amazon Alternate, Etsy Slot 2
ten-frames-real-angle-white-square-badged.png 1:1 Square Pure White + CMF Badge Technical Documentation, Red Dot Portfolio
ten-frames-real-front-desk-square.png 1:1 Square Classroom Wooden Desk Etsy Slot 3, Social Proof, Instagram
ten-frames-real-angle-desk-square-badged.png 1:1 Square Classroom Desk + CMF Badge Web Catalog Hero, Teacher Brochure
ten-frames-real-front-retouched-4x3.png 4:3 Wide Color-Corrected Workbench Documentation Banner, Blog Feature