Contour Vectorization: From Raster Graphics to SVG and DXF

What is Contour Vectorization?

Contour Vectorization traces the boundaries of shapes in a raster image, such as a PNG logo or a scanned graphic. It turns those pixel edges into editable vector paths around outer shapes, enclosed holes and internal details. Laserlinez provides SVG and DXF output for laser and CNC workflows.

Think of a nameplate with an outside border, two mounting holes and a logo inside. Its perimeter and holes need cutting profiles; the logo may need engraving rather than cutting through. The suggested cut and engraving groups help separate these tasks; you confirm which operation each path needs.

Automatic tracing can save substantial manual drawing time when a customer supplies only a bitmap. You can inspect and refine the generated paths instead of rebuilding each boundary by hand. If you already have a clean vector original, use it directly rather than rasterizing and tracing it again.

When to use Contour Vectorization

Choose Contour when the edges of a graphic define the shapes you want to cut or mark. Clear silhouettes and flat graphics are stronger starting points than photographs with shadows and texture.

• Logos, badges and nameplates: recover editable boundaries from a customer's PNG or JPEG and separate cut-through features from engraved detail.
• Signs, lettering and panels: prepare outer profiles and internal openings for laser cutting or CNC routing. Check small letters, narrow connections and mounting features at the final size.
• Cut-and-engrave products: keep the perimeter, holes and internal markings aligned in one design, then assign different operations in your laser software.
• Stencils and templates: trace the openings, then check which pieces must remain connected. Stencil bridges and workholding still require deliberate design decisions.

Contour, Centerline, or Tonal: choose by the paths you need

• Contour Vectorization follows shape boundaries. Choose it for the perimeter of a logo, cut-out lettering, or holes within a part.
• Centerline Vectorization follows the middle of existing strokes. Choose it for line drawings, signatures, or lettering when the machine should follow the drawn line rather than both edges of its thickness.
• Tonal Line Vectorization describes contrast, texture and structure using many vector lines. Choose it for detailed photographic linework, illustration, or vector engraving—not for closed part profiles.

Understand the three production groups

The group names describe intended roles, not machine settings. Use them to review the design before assigning cutting, scoring, or engraving operations.

• CUT_OUTER: the outside boundary of a part. For a cut-out badge, this separates the finished badge from the surrounding material.
• CUT_HOLES: enclosed openings intended to be cut through, such as mounting holes or cutouts inside the part.
• DETAIL: internal paths intended for vector engraving or scoring rather than cutting through. Scoring marks a line on the surface without separating the material.

Prepare a source with clear boundaries

Use the sharpest original JPEG or PNG available. Resolution matters because each important corner, gap and hole must be visible—not because a particular pixel count guarantees a usable trace.

• Inspect at full resolution: look for distinct foreground edges, readable lettering and open gaps. Enlarging a blurry thumbnail does not restore missing geometry.
• Prefer the cleanest export: JPEG compression can leave speckles or halos along edges that become rough or extra contours. Use a clean PNG original when available and retain useful transparency rather than flattening it onto a colored or textured background.
• Remove distractions: crop unrelated objects and remove decorative shadows, glows, or textured backgrounds. If a gradient obscures a boundary, use a flat-color version of the graphic. Preserve intentional holes, dots and narrow connections.
• Review at the intended size: details that look clear in a large image may be too small for the material, laser kerf, or router bit. Kerf is the width of material removed by a cut.
• Prefer a flat source: a straight-on scan or exported graphic is more reliable than a photograph taken at an angle. Tracing does not correct perspective or recover hidden dimensions.

SVG or DXF: choose the format your workflow needs

SVG is useful for vector editing and laser software such as LightBurn. DXF is commonly used for CAD/CAM handoff. Both describe geometry; switching file formats does not repair a poor trace or create machine instructions.

After import, set or verify a known overall dimension with the aspect ratio locked. Check at least one internal feature as well. A raster logo does not establish its real-world size and a correct overall width does not prove that a traced mounting hole has the required diameter.

Confirm the import units, especially with a unitless DXF. In LightBurn, check DXF import units or SVG import settings if the size is wrong. Correct the scale before applying kerf or tool compensation.

Prepare the contours for laser cutting and engraving

In LightBurn, Line mode follows the paths. Whether that cuts through or only scores the surface depends on the machine, material, power, speed and passes. Fill mode engraves enclosed areas; use it only where a filled result is intended, not simply because a contour is closed.

Complete engraving and enclosed cuts before releasing their containing part. For nested pieces, a single layer order may not be sufficient. LightBurn's Cut inner shapes first works within its configured ordering groups, so inspect the full preview rather than relying on the option or layer names alone.

For fitted parts, allow for the material removed by the beam. Apply appropriate kerf compensation in your laser software and test the fit. A thicker or thinner display stroke in the SVG does not change the laser's physical cut width.

Prepare the contours for CNC routing

Import the DXF into compatible CAM software and create the required toolpaths. For profile cutting, choose the correct side of the vector: normally outside a part and inside a hole. Select the cutter, cutting depth, feeds, passes and workholding for the job; add tabs or lead-ins where needed. Vectric's 2D Profile toolpath orders nested inner vectors before outer vectors; still check the complete job preview, including separate operations.

Check whether the cutter can reach narrow openings and internal corners. A round end mill leaves an inside corner radius. If a square-cornered mating part needs to fit, consider corner relief such as dogbone fillets where the design allows it, or adjust the design or tooling.

The result is 2D boundary geometry, not a 3D model or controller-ready G-code. Generate machine code in your CAM software with the post-processor for your controller.

Common contour problems and what to check

• Jagged edges or excessive nodes: inspect the source for compression and pixel stair-steps. Start with a cleaner graphic, then simplify selectively while preserving corners and small features.
• Missing holes or unwanted cutouts: compare with the source and the intended product. If openings or small features change unexpectedly, compare results with Remove Background on and off. A white region is not automatically a through-hole. Check the geometry and operation assignment separately.
• Repeated cuts or dark edges: inspect for duplicate or overlapping paths in the machine preview. Two edges around a thick source stroke are not necessarily duplicates; use Centerline if you need a path down its middle.
• Tiny gaps in a cut boundary: inspect and repair the affected profile. Do not close every open path automatically, because intentional engraving detail may contain open segments.