Pegas Nesting Bridge – User Guide

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Pegas Nesting Bridge — Manual v1.1

What’s new in v1.1: Color-coded DXF/SVG output. Every contour type — outer boundary, holes, cutouts — can now carry its own colour, saved once and reused on every export. Ideal for laser cutters (LightBurn, LaserGRBL) that map colours to cut/engrave layers, and for CNC operators who need instant visual separation between outer contours, drill holes, and pocket cuts.

🚀 Version v1.1.0 Color Vector📅 Last Updated: July 2026🛠️ Autodesk Fusion 360

What’s new in v1.1: Color-coded DXF/SVG output. Every contour type — outer boundary, holes, cutouts — can now carry its own colour, saved once and reused on every export. Ideal for laser cutters (LightBurn, LaserGRBL) that map colours to cut/engrave layers, and for CNC operators who need instant visual separation between outer contours, drill holes, and pocket cuts.

1. What each contour type means

The Bridge classifies every closed curve of a flat part into one of three categories. This is automatic — you don’t have to tag anything in Fusion. The classification drives both the DXF layer (if you enable layer separation) and the colour (if you enable custom colours).

1.1 Outer contour

  • What it is: the outer boundary of the part — the very shape a laser or router would follow around the perimeter to cut the piece free from the sheet.
  • How the Bridge detects it: the outer loop of the plate’s top (or bottom) planar face. Only the true plate boundary — not the perimeter of any internal pocket or step.
  • Typical use: the “cut” pass on a laser, the profile roughing toolpath on a router.
  • Default colour: black (#000000).

1.2 Holes

  • What it is: a closed circular feature that goes fully through the material.
  • How the Bridge detects it: an inner loop whose edges are all arcs / circles and whose bounding wall reaches the opposite side of the plate. If the wall dead-ends into a pocket floor (blind), the loop is treated as a cutout instead.
  • Typical use: through-drill positions on a router, “small cut” passes on a laser, or engraved reference marks for assembly.
  • Default colour: red (#FF0000).

1.3 Cutouts (slots, pockets, engravings)

  • What it is: any closed feature that is not a through-going circle. This bucket collects:
  • slots (round-ended, straight-walled, any orientation)
  • non-circular through openings
  • blind pockets and their floor perimeters
  • engravings (split-face sketch imprints, no depth)
  • nested pocket contours (bowl-in-bowl, step-in-step)
  • How the Bridge detects it: any inner loop that fails the through-circle test, plus outer loops of intermediate flat faces (pocket floors).
  • Typical use: engraving passes, pocketing toolpaths, feature-highlight layers.
  • Default colour: blue (#0000FF).

1.4 Priority when contours overlap

When two contours occupy essentially the same 2D footprint (e.g. a pocket top opening and its slightly-shrunk floor), the longer contour is kept and the duplicate is dropped. If the survivor was tagged as outer and the duplicate as cuts, no re-tagging happens — the outer stays outer. In practice this means:
– Duplicate lines never appear in the DXF
– Slot outlines join into a single object in AutoCAD (same colour on same layer)
– Nested features are preserved as long as they are noticeably smaller than their parent (< 85 % on either axis)

2. Where to find the feature

Palette → Export DXF/SVG tab → Settings block

The new controls sit below “Save DXF / Save SVG”:

[✓] Use custom colors                           [ Reset colors ]

    Outer contour           [ colour ]  [ ] Save default
[ ] Holes on separate layer [ colour ]  [ ] Save default
[ ] Cutouts on separate     [ colour ]  [ ] Save default

DXF grouping [dropdown]                         [ ] Save default

3. Step-by-step: turning colours on

  1. Open Export DXF/SVG tab.
  2. Tick Use custom colors. The three colour swatches wake up (become clickable).
  3. Click a coloured swatch. Windows opens its native colour picker — pick from the palette or type a hex value (#FFAA00, RGB (255, 170, 0), HSL sliders — everything you expect from a picker).
  4. Repeat for the other two categories.
  5. Click Export DXF / SVG. Open the resulting file in your CAM software — contours arrive colour-coded.

To turn colours off without losing your palette: untick Use custom colors. The swatches keep their values but grey out. The export writes plain black (BYLAYER), just like the pre-v1.1 output.

4. Saving colours as defaults

Every colour swatch, every folder input, and the DXF grouping dropdown carries a Save default checkbox on its right.

  • Tick Save default next to a control → the current value is written to pegasnesting_prefs.json in the add-in folder.
  • Restart Fusion / re-open the palette → the value auto-loads. Save default stays ticked as long as the current UI value matches the saved one.
  • Change the value manually (edit text, pick a new colour, choose a different grouping) → Save default un-ticks itself. Nothing is written to the prefs file until you tick it again.

This mirrors the “Save default” pattern used across the Pegas ecosystem: the user is always in control of when a value becomes the persisted default.

5. Reset colors button

Click Reset colors to snap all three swatches back to #000000. All three Save-default marks clear automatically. The prefs file is not touched — if you want the reset to be permanent, tick the three Save default boxes explicitly. This lets you produce a clean single-colour DXF/SVG in one click without erasing your saved palette.

6. Save default for other settings

6.1 Export Folder

Both Tab 1 (Export Nesting) and Tab 3 (Export DXF/SVG) now have their own Save-default checkbox next to the Browse button. Set a folder, tick Save default, and every future palette open drops you into that path. The two folders are stored independently — you can send nesting exports to one directory and simple DXF exports to another.

6.2 DXF grouping

The grouping dropdown (No grouping / Part as block / Contours as blocks) also has a Save default. Pick the mode you use most often, tick the box, and every export defaults to it.

7. Compatibility with CAM software

DXF colours are written using both the classic ACI code (group 62) and the modern 24-bit RGB code (group 420). This dual-write covers every reader we know of:

Software Reads Notes
AutoCAD 2004+ RGB (420) exact colour
LightBurn ACI (62) maps to LightBurn layer colour
CorelDraw RGB (420) exact colour
LaserGRBL ACI (62) reads standard layer colours
DeepNest ignores colours uses layers/grouping for nesting logic
Older AutoCAD LT / AutoCAD DWG viewer ACI (62) closest of the 7 basic colours

Pure black (#000000) is written as ACI 7 only — the RGB code is intentionally omitted because some readers (LightBurn included) misinterpret RGB(0,0,0) and fall back to a layer palette colour that often lands on brown.

SVG uses simple stroke="#RRGGBB" per path — every browser, Inkscape, Illustrator, and modern laser controller reads it.

8. Recommended workflows

8.1 Laser cutting (LightBurn)

  • Outer: black — cut pass, high power
  • Holes: red — cut pass, high power (through holes)
  • Cutouts: blue — engrave pass, low power
  • Enable Holes on separate layer and Cutouts on separate layer so LightBurn keeps them on distinct layer entries too. Import → three ready-to-tune layers.

8.2 CNC router with V-carve / Fusion CAM

  • Outer: black — profile pocket
  • Holes: red — drilling operation
  • Cutouts: blue — pocket / engrave
  • Grouping = Contours as blocks so each feature is a single selectable object in AutoCAD before you send it to CAM.

8.3 Documentation-only exports

  • Untick Use custom colors → single-colour black output for shop drawings, laser cutter file inspection, or vendor communication.

9. Troubleshooting

My slot exports in mixed colours (some blue, some black).
Update to v1.1. Prior versions could route parts of a slot outline through the outer bucket because a curved pocket cavity accidentally passed the flat-face filter. v1.1 uses strict planar-surface detection, so slot outlines are fully classified as cuts.

Nested pocket (bowl-in-bowl) — only the outer circle shows.
v1.1 adds an edge-based fallback that finds horizontal contours living between two curved surfaces. If you still see only one circle, tick the debug checkbox, re-export, and share the debug/debug.log file with support.

Save default is ticked but the colour doesn’t come back after restart.
Confirm pegasnesting_prefs.json exists in the add-in folder. Some Fusion installs sandbox the file — support can help identify the correct path.

Reset colors doesn’t persist.
Intentional. Click Save default on each swatch after the reset if you want the black default written to disk. This prevents accidental erasure of a carefully-tuned palette.

LightBurn shows my black lines as brown.
Update to v1.1. This exact case is what motivated the switch to ACI-only encoding for pure black.

10. Reverting to v1.0 behaviour

You can disable the new feature at any time without downgrading:
– Untick Use custom colors → output is single-colour (BYLAYER), identical to v1.0.
– Leave the layer-separation checkboxes on if you still want DXF layers.
– The Save-default folders and grouping have no negative side effects — they only change what shows up in the fields on palette open.

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