Case Study 13: Multi-Element Lens PDF Drawing Export

Goal

This case study shows how a user enters a multi-element lens in the editable UI table, adds per-surface fabrication metadata, and exports an ISO-style PDF drawing package.

The example is a compact cemented triplet. It is not a released production design; it is a reproducible workflow that proves the UI can carry optical prescription data into a drawing-oriented output.

The screenshots and output files are generated with:

python -m KrakenOS.UI.capture_lens_drawing_pdf_case_study_screenshots

The scriptable example is:

python KrakenOS/Examples/Examp_Lens_Drawing_PDF_Export.py

Download the generated outputs:

• multi_element_lens_fabrication_drawing.pdf

• triplet_surface_properties.json

Input The Surface Table

Start the UI with python -m KrakenOS.UI.layout_editor. Create this table with Add surface and direct cell edits:

Row	Surface	Name	Rc [mm]	Thickness [mm]	Diameter [mm]	Glass
0	Object	Object	NA	25.0	32.0	AIR
1	Standard	E1 front crown	42.0	6.0	28.0	N-BK7
2	Standard	E1/E2 cement interface	-28.0	3.2	27.5	N-SF5
3	Standard	E2/E3 cement interface	64.0	5.8	27.0	N-LAK22
4	Standard	E3 rear surface	-55.0	42.0	26.5	AIR
5	Image	Image	NA	0.0	32.0	AIR

Rows 1 through 3 have real glass after the surface. With zero air gap between them, the drawing exporter identifies one cemented three-element group. Row 4 is the rear surface because the material after it is AIR.

The editable table contains the triplet prescription before drawing export.

Input Drawing Properties

Choose File -> Lens Drawing Surface Properties... or File -> Export Lens Drawing.... The export command opens the same dialog before asking for a PDF filename.

Enter fabrication metadata on the optical surface rows:

Row	Clear aperture	R tolerance	CT tolerance	Dia tolerance	3/ form	Coating / notes
S1	26.0	+/-0.035	+/-0.05	+0/-0.03	3/ 3 (0.5) lambda=632.8 nm	R(avg) < 0.75% from 450-650 nm
S2	25.5	+/-0.025	blank	blank	3/ 3 (0.5) lambda=632.8 nm	cement: NOA 61 or equivalent
S3	25.0	+/-0.030	+/-0.05	blank	3/ 3 (0.5) lambda=632.8 nm	cement: NOA 61 or equivalent
S4	24.5	+/-0.040	blank	+0/-0.03	3/ 3 (0.5) lambda=632.8 nm	R(avg) < 0.75% from 450-650 nm

Blank fields are allowed. They become placeholders or omitted notes in the drawing. The dialog stores data in each row’s advanced["DrawingProperties"] dictionary and can also save/load a JSON sidecar.

Each row maps to one physical optical surface in the table.

Export The PDF

Choose File -> Export Lens Drawing.... After reviewing the properties dialog, click Apply && Continue and choose a PDF filename.

The generated PDF has four pages:

• one assembly page for the cemented triplet;

• one individual drawing page for each of the three elements.

The assembly sheet shows the cemented group, total thickness, outside diameter, EFL/BFL entries, cement notes, and surface radius table.

Element 1 shows its center thickness, diameter tolerance, left/right surface radii, clear apertures, coating notes, material note, and edge note.

Element 2 inherits the cement-interface metadata from the shared surface rows.

Element 3 carries the rear-surface coating note and final assembly inspection note.

Run The Validator

Use this check after editing drawing properties, element identification, or PDF export code:

python -m KrakenOS.UI.validate_lens_drawing_pdf_case_study
python -m KrakenOS.UI.validate_lens_drawing_properties

The first validator proves that this case study still identifies one cemented three-element group, round-trips the JSON surface-property sidecar, and writes a non-empty PDF. The second validator checks the lower-level drawing-property schema and two-element cemented group export.

What This Proves

This case study exercises the engineering-output side of the UI:

• table cell prescription entry for a multi-element lens;

• automatic cemented-group identification from material and zero air gaps;

• per-surface drawing metadata stored in row Advanced data;

• editable JSON sidecar export/import for drawing properties;

• assembly-page and element-page PDF drawing generation;

• surface radius, clear aperture, coating, cement, material, centering, edge, and miscellaneous note export.

Important Limitation

The exported PDF is a fabrication starting point, not a controlled released drawing. Before manufacturing, verify tolerances, coating requirements, glass melt data, edge/chamfer details, drawing number, revision policy, title block, and vendor-specific drawing standards.