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🔬 GRIN Fixture Auto-Calibration Framework

xPRIMEray / GD_xPRIMEray – Engineering Study Architecture

🧠 Purpose

Establish a repeatable, measurable, and automatable framework for:

  • Characterizing GrinFilmCamera behavior
  • Defining valid parameter operating regions
  • Enabling Codex-assisted execution
  • Progressing toward auto-calibration of GRIN ray paths

This document defines the A / B / C execution model and integrates it into the broader xPRIMEray architecture.

🧱 Core Philosophy

We are not just rendering.

We are building a:

Controlled optical laboratory inside the renderer

Where: - Scenes = fixtures - Rays = measurable signals - Parameters = controllable inputs - Logs = instrumentation - Codex = execution + analysis agent

🔺 A / B / C Framework

A — Safe Execution Harness (Operations Layer)

Goal

Enable deterministic, bounded, reproducible test execution.

Requirements

  • Fixed entrypoint script(s)
  • Controlled scenes only
  • Non-destructive commands
  • Predictable output directory
  • Codex-friendly interface

Example Entry Script

/scripts/run_fixture_baseline.sh

Responsibilities

  • Load fixture scene
  • Apply parameter set
  • Run renderer in bounded mode
  • Emit logs to structured location

B — Measurement & Logging Layer (Signal Layer)

Goal

Convert ray behavior into quantifiable engineering metrics

Required Metrics (Initial Set)

  • Hit Success Rate
  • Miss / Divergence Rate
  • Bend Angle Distribution
  • Radial Deviation
  • Final Intercept Error
  • Path Smoothness (oscillation detection)
  • Symmetry Error (if applicable)

Output Format

/output/fixture_runs/{timestamp}/
  ├── params.json
  ├── ray_log.txt
  ├── metrics.json
  └── summary.txt

Key Principle

If it cannot be measured, it cannot be calibrated.

C — Codex Execution Workflow (Integration Layer)

Goal

Enable Codex to act as a controlled engineering operator

Standard Interaction Pattern

  1. Show command
  2. Confirm non-destructive
  3. Execute
  4. Summarize results

Example Prompt Pattern

Run the GRIN fixture baseline.
Show command first, then execute, then summarize metrics.

Responsibilities

  • Execute harness scripts
  • Parse output artifacts
  • Compare runs
  • Suggest parameter adjustments

🧪 Fixture-Based Characterization

Definition

A fixture is a controlled scene designed to test specific GRIN behaviors.

Fixture Components

  • Known emitter position
  • Known target surface or region
  • Defined GRIN field
  • Expected ray behavior

Example Fixture Types

  • Radial focusing lens
  • Symmetric field test
  • Wormhole throat proxy
  • Flat-to-curved transition field

📊 Phase Plan

Phase 1 — Baseline Harness (A)

Deliverables

  • One fixture scene
  • One execution script
  • Basic logging

Success Criteria

  • Codex can run fixture without errors
  • Output artifacts generated consistently

Phase 2 — Metric Instrumentation (B-lite)

Deliverables

  • Core metric extraction
  • Structured metrics.json

Success Criteria

  • Runs produce comparable numeric outputs
  • Basic pass/fail thresholds definable

Phase 3 — Comparative Analysis (B-full)

Deliverables

  • Run-to-run comparison tooling
  • Delta reporting

Success Criteria

  • Detect parameter sensitivity
  • Identify stable vs unstable regions

Phase 4 — Codex Workflow Integration (C)

Deliverables

  • Codex-compatible script interface
  • Standardized prompt templates

Success Criteria

  • Codex can execute + summarize runs reliably

Phase 5 — Parameter Sweep Engine

Deliverables

  • Controlled parameter sweeps
  • Multi-run aggregation

Success Criteria

  • Parameter space begins forming stability maps

Phase 6 — Calibration Engine

Deliverables

  • Optimization loop
  • Objective function (error minimization)

Success Criteria

  • Identify best-fit parameter sets for fixture

Phase 7 — Auto-Calibration

Deliverables

  • Fully automated loop:
  • run → evaluate → adjust → repeat

Success Criteria

  • System converges to valid GRIN configurations autonomously

🧠 Architectural Integration

This framework connects to:

  • RayBeamRenderer → ray path generation
  • GrinFilmCamera → parameter control surface
  • FieldSource3D → GRIN field definition
  • Future: ResearchModeConfig

🔮 Long-Term Vision

A system where:

  • Any fixture can be loaded
  • Codex executes a test suite
  • Metrics are generated automatically
  • Optimal parameters are proposed

Resulting in:

A self-characterizing optical simulation engine

⚡ Immediate Next Step

Implement:

  1. First fixture scene
  2. Single execution script
  3. Minimal metrics output

Then validate with Codex execution.

🧬 Tagline

We are not tuning parameters manually.

We are teaching the system how to understand itself.

🚀 End of Document