Leadlight Designer: From Picture to Numbered Pattern

How to use it, step by step

1. Jobs. Name the job in the bar above the tools. It autosaves in this browser under that name and reopens next visit; Open job switches between jobs, New job clears the work surface for the next one, Save file / Open file move a job as a .json. Undo covers everything, including loading a picture, Turn into pattern, borders, size changes and New job.
2. Load. Drop a photo or a scanned cartoon on the Picture tab, or pick a sample, or start a blank panel. The picture sits under the design as a backdrop; whatever is already on the work surface (a border, shapes, lines) stays. A drawing on paper with an outer line is straightened to that line on the spot — the outer line is the panel edge and the margin, table and tape are dropped (Reset photo undoes it).
3. Design setup. Say what is fixed: Must fit an opening (the outside stays exactly as typed; pictures are fitted or stretched inside it and inside any border) or Free (the panel follows the picture; a border keeps its widths and is re-laid). Set the shape (rectangle, arch, circle, oval, octagon). Change any of it later: the border is re-laid, never stretched, and the artwork reframes inside.
4. Prepare. If the panel looks angled the tool says so: press Straighten and drag the four corners onto the panel corners. Use Patch to paint out a hand or a shadow.
5. Trace. Choose Lead came or Copper foil, draw a Keep-detail box over any part that needs finer pieces, then press Start conversion. The questionnaire settles where the picture goes (inside your border, best fit, stretched or as an insert), a frame found in the picture, symmetry, holes, true circles, the safe fixes and — under More trace settings — style, detail, colours, contrast and brightness. A line is found as a ridge: dark with lighter paper on both sides within a few pixels, at three widths so pencil hairlines and thick marker both count — never as "darker than some threshold", so a shadowed corner or a gradient is not an edge. Start conversion opens the pane; it stays open while you adjust, and the red lines on the work area are the finished pattern as it would be kept — straightened, smoothed, cleaned, mirrored, coloured — so tick and untick until it is right, then Finish conversion keeps it (Stop keeps only the picture; Restart conversion reopens the pane with the same choices). The pane runs in the order the work happens: 1 the outline (the outer line of the drawing, the picture's edge, a panel shape, or the subject's own outline for a butterfly or a bird with the background dropped), 2 the lines (ink threshold, gap bridging for a pen that skipped, writing ignored, filled shapes as pieces, contrast), 3 smoothing and clean-up, 4 colour infill from the picture or left clear for colouring by hand. While it is open the work area shows, in red, the lines the trace would find, and the count of pieces — every setting updates it, so adjust until the shapes are right before pressing Make the pattern. "The picture shows the left half" (or right, top, bottom) traces a half drawing and completes it with its mirror image. The result is CAD-clean: straight runs exactly straight across junctions, every curve one smooth run of came within its bend radius, no hooks at junctions.
6. Style. Once the picture is in, pick a pattern style from the previews (bold lead through to very fine foil, or line drawing), or set the Detail slider yourself.
7. Review flags. Press Review flags. Fix the safe ones does the tiny pieces, slivers, deep curves and obvious loose ends; Next flag walks you through the rest with a Bridge, Split or Extend button for each — a loose end shows its choices (A straight on, B to the nearest line) drawn on the pattern.
8. Subject in a sketch. A drawing of a subject on plain paper — a dove, a leaf — converts in two steps. Step 1 shows the outline alone on the work area, everything outside dimmed: a rubber band around every mark the subject is drawn with, sitting just outside the outer lines: a loop around everything, then every stretched length longer than Pull into gaps allows is pulled in onto the ink beneath it. Low leaves the gaps between feather tips spanned straight; high follows every bay. A gap is between two strokes: along one continuous line the band follows it into every bay, however narrow. A pin is all-powerful: the band passes through every pin, even inside the drawing (a notch cut in). A point stays a point; a hair of a stroke is never a dag. Which part: the Picture tab asks as soon as a picture is loaded — Select the part and drag a box round it (the bird, the plate), and the conversion opens for that part with its own outline; or Whole picture. In the pane, Which part changes the box; the page's edge or a frame round the picture is never the subject. A finished subject is saved to your library as an object. Set the finished width of the subject, the vacuum, pin where the edge must reach, ignore what is not the subject. Step 2 traces the lines inside; they need not meet yet — loose ends are kept and flagged, joined only over short gaps. Step 0 of the pane straightens a skewed photo first (by hand, or automatically to the drawn outer line of a framed sketch); the version number on the page and in the pane says which build is running.
9. Jobs list. Every job autosaves in this browser once it has content. Jobs… lists them with when they started, last edited, pieces, lines, lead or foil, size and picture; open or delete any, delete all with 0 pieces, or delete all but the open one. Save file keeps a copy you can move between computers.
10. Line here. Missed a line? In the conversion pane press Line here, then click the work area on the line: the dark line under the click is followed as far as it stays that dark and traced, whatever the finder thought. Click the marker to remove it. Ignore does the opposite for a mark that is not a line.
11. Smooth and straight. Two settings, because they conflict: Smooth curves irons the raster steps and the wobble of the glass out of every curve (a long wavy run keeps its wave); Straighten runs turns a nearly straight run into an exactly straight, locked line up to the bow you allow (off, 1.5, 3 or 6 %). A photo of a window starts with straightening off. Square the border squares the strips of glass and the corner blocks round the edge.
12. Photo of a real leadlight. A photograph of an existing window is read as its black lines only, whatever read is chosen: a fainter came carries on from the black it joins only where it is thin and nearly as black (dark glass beside the came is neither), the glass is never divided by its colour or texture, no cut is invented across a piece, a loose end is joined 3 mm on at most, and each piece takes the colour of the glass under it (matched to stock glass, or kept as it is with a free palette). Leave "Merge pieces smaller than" off: the pieces are the pieces (at 31 mm it merges the tail). To make all the grass one green afterwards: select a grass piece, pick the swatch, Paint all of this glass.
13. Colours and drawn lines. Read the picture as: a drawing (dark strokes are the lead), a picture of colours (every colour change is a line), or both — a colour change is a line and so is every stroke drawn over the colour, so a coloured region cut into smaller pieces by drawn lines traces as drawn. A soft change of colour inside a piece (a gradient, the mottle of the glass) is not a line: two neighbouring colour regions whose mean colours are close become one piece; a drawn line between them always keeps them apart.
14. No glass. A piece of glass is its own thing. Delete piece (Inspector, or right-click) leaves no glass there: the space is hatched, unnumbered and not cut. Lead lines stay, because lead is the design; with copper foil the lines around a deleted piece go faint — no glass, no foil. A void divided by a line stays void; a closed shape drawn inside it is new glass. Right-click the space for Glass here again, or press the no-glass button above the work area. To make one piece of two, merge into a neighbour from the Inspector.
15. Markers. With the conversion pane open and "The subject's own outline" chosen, Pin then click the work area where the border must touch; Ignore then click a smudge, a word or any mark that is not the drawing. Click a marker to remove it; Clear markers removes them all. The wrap and the trace update at once. The outline follows the outer edge of a thick stroke; markers are saved with the job and cleared when a new picture is loaded.
16. Views. The view select above the work area: realistic glass, lead lines, cut lines, came runs, the photo under the lead, the photo through the glass, and Original picture only — a labelled view of the picture alone; your lines and came are untouched and come back with any other view.
17. Adjust. Coordinates read the CAD way: x and y from the bottom-left corner of the panel, y up, angles anticlockwise from horizontal (0° flat, 90° straight up); the readout at the bottom-left of the work area and every typed x / y use that. Drag junctions and the neighbours follow (junctions on the panel edge slide along it while Edge lock is on). Every plain straight line is straight-locked: a junction on it slides along the line instead of bending it into angles — to bend one on purpose untick "straight" in the Inspector or press Curve handles; the toolbar switch turns the lock off for everything. A free end dragged near a line or a junction snaps onto it and joins it. Clicking a straight line selects its whole run across junctions — a border side, say — and a second click takes one segment; the readout shows the length and angle. Draw line adds a line between any two points, even in free space; Erase line removes one. Right-click any piece, line or junction for its menu. Border and Shape are on the toolbar; shapes drag and resize as objects.
18. Symmetry and objects. Turn Symmetry on in the toolbar and every line or shape you add is mirrored across the dot-dash axes; painting mirrors too. Shift-click lines (or a piece) and press Make object to turn them into a named object — drag it, rotate, flip, scale, copy it, or save it to your library and place it in another design.
19. Inspector. Whatever you click shows up as numbers on the Pattern tab: glass, size, how many other pieces share the shape, and grain for a piece; centre, width and height for a shape; centre and radius for a circle; position, size and rotation for an object; x and y for a junction; the came size for a line, with Make it vertical / horizontal / 45° when it is nearly there. Type a value and press Enter. Drag a selected line and the whole line bends smoothly with its ends fixed; Curve handles shows its bends as squares with Bézier handles for exact shaping; the white dots move one bend at a time.
20. Symmetry. With Symmetry on, every edit is mirrored: move a junction or a bend, smooth, straighten or erase a line, drag a shape or a circle, and the mirror-image lines follow. Junctions on the axis stay on it. Shapes, bevels and library objects drop with their mirror copies.
21. Delete a piece. Select a piece and press Delete piece (strip, Inspector, right-click or the Delete key): it merges into the neighbour it shares the most lead with, and the Inspector lets you choose a different neighbour. A shape is simply removed.
22. Borders and bevels. Border on the toolbar opens a gallery sized to your panel. Adding a border to a design that already has one shrinks everything again; tick "remove the existing outer band first" to swap a border. Shape, Bevel and library objects float on the cursor with width, height and angle in the Inspector; click to drop them, and they never leave the panel. A rectangular bevel dropped on a border band spans the band; if the band is the wrong width the strip offers to widen the whole border, the corner blocks only, or to set the bevel in as it is. Anywhere else a bevel is a solid: the lines around it stop at its edge. Add your own bevel sizes on the Pattern tab.
23. Circles. Pick the Circle tool and click any arc of a sketched circle: the whole ring is followed round, fitted and replaced with a true circle, with the lines that met it joined on. The Inspector then shows its centre and radius, which you can type, plus Centre in panel and Concentric. Drag inside the circle to move it. Undo if it is not what you meant.
24. Colour. Pick a swatch and click pieces, or use the colour picker in the piece list or the Inspector for any colour at all. Mirror keeps the opposite side matching. Grain sets the direction arrow that prints on each piece. The Realistic view lights the glass from behind; Photo under the lead shows the came over the picture, Photo through the glass shows both.
25. Came and print. Choose the came: lead 1/4" as the default, 3/16" on fine parts, 3/8" at the frame — any line can take its own size (Inspector → Apply to its run), and the Came tab counts sticks per size and checks that every side of the border carries the same edge came. Lead bends to about one and a half faces of radius (10 mm for 1/4"), zinc hardly at all, foil as tight as you like: a curve too tight for its came is flagged with the notches and slots to cut drawn on it, or eased with one click. Changing the edge came (U channel or H section) asks whether the band takes up the difference or keeps its glass. Print tab gives 1:1 PDF sheets with an assembly map, glass list and came-run sheet.

An illustrated manual is coming once the tool settles down; this list is the whole workflow until then.

Why designers fight their pattern software

Glass Eye 2000, the program most studios run, dates from the late 1990s and models a design the way a drawing program does: as a bag of lines that happen to touch. That is fine until the client wants the tulip a little taller. Now the four lines that met at the tip of the petal must all be moved to the same new point, the two pieces either side must be re-closed, the numbers re-issued, and the cut list re-run. A designer told us he spends a good part of every week doing exactly that.

The fix is a data model, not a feature. Here the pattern is a planar graph: junctions, the lead lines between them, and the pieces computed as the faces the lines enclose. Drag a junction and every line into it follows with a falloff; the pieces on both sides re-close by definition, because they were never stored. Add a line across a piece and it becomes two pieces, each inheriting the parent's glass. Delete a line and the two pieces merge and the leftover junction dissolves. Borders and shapes are inserted the same way - every line they cross becomes a junction - which is why a circle dropped onto a background becomes a real island with a real hole to bridge, not a picture of one.

Lead line, cut line and the heart of the came

H-section lead came comes in face widths from 3/16 inch (4.8 mm) up to 1/2 inch (12.7 mm), but the number that decides the cut is not the face - it is the heart, the web between the two channels, about 1/16 inch (1.6 mm) on lead and around 1/32 inch on copper foil. The glass sits in the channel either side of the heart, so each piece is cut half a heart smaller than the line on the cartoon. Three-blade pattern shears exist for exactly this reason: they remove a 1.6 mm strip (or 0.8 mm for foil) as you cut the paper pattern apart. Choose the came in the Came tab and the tool draws both views: lead lines for the layout board, cut lines for the pattern shears and the glass, and prints either at full size.

Came runs: fewest cuts, fewest joints

Watch a good glazier lead up a panel and the order is never piece by piece. The long lines go down first, each as one continuous length of came, and the short lines are cut to butt into them. Every place a came stops is a cut, a mitre, a joint and a solder bead on both faces, so a layout with thirty long runs is quicker and stronger than the same panel in ninety short ones. The tool works this out for you: at every junction it pairs the two lines that run most nearly straight through (lead will happily follow a bend of 30 degrees; zinc will not), chains them into runs, and reports the count, the total metres and the number of 1.83 m sticks to buy. The Came runs view colours each run and numbers it, and the printed came-run sheet lists them longest first - the order to lay them. Click any junction to change which pair runs through it when you know better than the geometry.

Questions from the bench

The panel was always lines. The pieces were only ever the light between them.