Cad Build123d Six View Checks

Build123d Six-View Checks

Prerequisite: Load cad-build123d-general first for orientation-map and export-mode conventions.

Purpose

Create a repeatable visual QA step that exports six labeled views (front, back, left, right, top, bottom) after geometry rebuilds. This helps catch wrong-face edits, mirrored features, hidden split seams, and accidental wall penetrations before printing.

Source of Truth

This skill is the source of truth for six-view verification workflow in CAD projects in this repo.

• Orientation labels use the model's global axes: front=+Y, back=-Y, left=-X, right=+X, top=+Z, bottom=-Z.
• File naming convention: <part-name>_<view>.png.
• Output folder convention: <project>/exports/views/.

Preferred Tools

1) OCP CAD Viewer (interactive, best first choice)

Use when the user wants quick manual confirmation in VS Code.

• VS Code extension: OCP CAD Viewer
• Python package: ocp-vscode
• Strength: fastest way to inspect the exact face orientation with selection and measurements.

Workflow:

1. Rebuild the model script.
2. Open in OCP CAD Viewer.
3. Capture six snapshots using fixed camera directions.
4. Save to exports/views/ with the naming convention above.

2) Headless snapshot pipeline (automated CI-style checks)

Use when the user wants reproducible images generated on every run.

Recommended Python stack:

• trimesh
• pyvista
• pillow

Install:

pip install trimesh pyvista pillow

Integration Pattern

Add a verification switch in CAD scripts so six views can be enabled without affecting production exports.

VERIFY_VIEWS = True
VIEWS_DIR = EXPORT_DIR / "views"
PART_BASENAME = "my_part"

Run order at end of script:

1. Build part
2. Export STL/STEP
3. If VERIFY_VIEWS is true, generate six-view PNGs
4. Print generated file paths

Reference Camera Map

Use orthographic projection for QA images. Perspective can hide alignment issues.

Quality Checklist

For each generated view, verify:

1. Outer silhouette matches expected dimensions.
2. No unintended wall penetrations.
3. No mirrored features across +Y/-Y or +X/-X.
4. Split seams are understood (boolean partition lines vs true recesses).
5. Labeling is consistent with orientation map.

Quick Triage: "Is this a real dent or a split seam?"

1. Compare opposite faces (front vs back, left vs right).
2. If the line appears only where booleans intersect but no face-depth shift exists, it is likely a coplanar split seam.
3. Confirm with geometry queries (face normal and center position) before changing dimensions.
4. If needed, run a cleanup pass (for example, part.clean() where safe).

Minimal Verification Helper (drop-in)

Use this helper pattern when a project asks for repeatable image checks.

from pathlib import Path

def report_expected_views(base_name: str, out_dir: Path) -> None:
    names = ["front", "back", "left", "right", "top", "bottom"]
    out_dir.mkdir(parents=True, exist_ok=True)
    for n in names:
        print(out_dir / f"{base_name}_{n}.png")

This helper does not render images by itself; pair it with your selected viewer/render backend.

Common Failure Modes

See Also

• Related skill: cad-build123d-general (orientation map, export workflow)
• Related skill: cad-build123d-tools (viewer and tooling catalog)
• Sister skill: cad-render-images (publication renders \u2014 hero, exploded, cutaway, turntable). This skill = QA snapshots; that skill = documentation/marketing renders.
• OCP CAD Viewer: https://github.com/bernhard-42/vscode-ocp-cad-viewer