Lens Fabrication Drawings
=========================

``File -> Export Lens Drawing...`` generates an ISO 10110-style PDF fabrication
drawing for refractive lens elements in the editable surface table. It is meant
as a mechanical drawing starting point: verify tolerances, coating notes, and
shop-specific requirements before releasing it for manufacture.

Surface Property Workflow
-------------------------

Before writing the PDF, the UI opens ``Lens Drawing Surface Properties``. The
same editor is also available from ``File -> Lens Drawing Surface Properties...``
and the surface right-click ``Advanced`` menu.

Each row in that dialog maps to a physical optical surface row in the main table.
The values are stored in that surface row's
``advanced["DrawingProperties"]`` dictionary, so saving the layout as a Python
file preserves the fabrication metadata alongside the prescription. The dialog
also has ``Save JSON...`` and ``Load JSON...`` for an editable sidecar file that
can be reviewed or versioned before PDF export.

.. figure:: ../_static/manual/ui/lens_drawing_surface_properties.png
   :alt: Lens Drawing Surface Properties dialog with clear aperture and ISO-style tolerance fields
   :width: 100%

   ``Lens Drawing Surface Properties`` stores fabrication metadata per optical
   surface before PDF export.

The sidecar format is:

.. code-block:: json

   {
     "format": "krakenos.lens_drawing_properties.v1",
     "version": 1,
     "surfaces": [
       {
         "surface_index": 1,
         "label": "1",
         "surface": "Standard",
         "name": "Front surface",
         "material": "N-BK7",
         "properties": {
           "clear_aperture_mm": 24.0,
           "radius_tolerance": "+/-0.035",
           "thickness_tolerance": "+/-0.1",
           "diameter_tolerance": "+0/-0.025",
           "form_error": "3/ 3 (0.5) lambda=632.8 nm",
           "irregularity": "4/ -",
           "scratch_dig": "5/ 40-20 (MIL-PRF-13830B)",
           "coating_note": "1/4 wave MgF2 @ 550 nm",
           "material_note": "670/472",
           "cement_note": "NOA 61 OR EQUIVALENT",
           "centration_note": "14/ 1'",
           "edge_note": "Protective chamfers as needed",
           "other_requirement": "Edge blacken after coating"
         }
       }
     ]
   }

Supported Fields
----------------

``clear_aperture_mm`` is numeric and must be positive when present. The other
fields are text because fabrication drawings often use tolerance strings rather
than scalar values.

``radius_tolerance``
  Appended to the radius cell, for example ``R 34.53+/-0.035 CX``.

``thickness_tolerance``
  Appended to the center-thickness dimension on the element page.

``diameter_tolerance``
  Appended to the outside-diameter dimension on the element page.

``form_error``, ``irregularity``, ``scratch_dig``, ``surface_note``
  Exported into the ISO-style surface table as the ``3/``, ``4/``, ``5/``, and
  ``6/`` callouts.

``coating_note``
  Exported as the coating/surface note callout for the left or right surface.

``material_note``
  Appended to the glass material cell, useful for melt or glass-code notes.

``cement_note``
  Used for cemented interfaces in the assembly page table.

``centration_note`` and ``edge_note``
  Added to the element-page notes section for centering and edge/chamfer
  requirements.

``other_requirement``
  Free-form literal text for any other surface-specific fabrication requirement.
  It is exported in the element-page notes section as ``OTHER``.

Example In A Layout File
------------------------

The same metadata can be authored directly in a saved Python layout:

.. code-block:: python

   surfaces.append({
       "surface": "Standard",
       "name": "Front surface",
       "rc": 34.53,
       "thickness": 9.0,
       "diameter": 25.0,
       "glass": "N-BK7",
       "advanced": {
           "DrawingProperties": {
               "clear_aperture_mm": 24.0,
               "radius_tolerance": "+/-0.035",
               "thickness_tolerance": "+/-0.1",
               "form_error": "3/ 3 (0.5) lambda=632.8 nm",
               "scratch_dig": "5/ 40-20 (MIL-PRF-13830B)",
               "coating_note": "1/4 wave MgF2 @ 550 nm",
               "other_requirement": "Edge blacken after coating",
           }
       },
   })

Reference Behaviour
-------------------

The included ``attachment/Lens/isop_32323.pdf`` Edmund Optics drawing shows the
same style of data: an assembly sheet plus individual lens sheets containing
radius tolerances, clear aperture, ISO ``3/`` through ``6/`` surface callouts,
coating notes, material notes, and cement notes. KrakenOS fills the matching
fields when present and leaves placeholders when a shop-specific value is still
unknown.