Why SVG Artwork Imports at the Wrong Size in Laser Software

When laser SVG scale is wrong, the artwork may retain its shape while arriving at the wrong physical dimensions. The usual handoff points are document units, width, height, viewBox, DPI assumptions, transforms, strokes, clipping, or application-specific export behavior.

Carry one known-size reference object through every export and import. Measure it in the laser software before changing the artwork or machine settings; that tells you whether the scale changed in the file handoff or later in the device workflow.

Compare One Known Dimension at Every Handoff

Start with the intended physical size, not the on-screen zoom. Add a reference rectangle or outer boundary with a deliberate width and height, then record those values in the source design.

An SVG can contain:

• Physical width and height.

• A viewBox coordinate system.

• Explicit or missing units.

• Nested group transforms.

• Percentage dimensions.

• CSS styles.

• Strokes extending beyond the path.

• Clipping masks and hidden objects.

Two applications can interpret an underspecified SVG differently. A browser preview may display the artwork attractively while a laser program must infer the relationship between internal coordinates and physical units.

At each handoff, compare the same reference:

1. Source document.

2. Exported SVG in a viewer or editor.

3. Imported bounding box in the laser software.

4. Final machine test on suitable material.

If the reference changes immediately after import, diagnose the file or import settings. If it imports at the intended size but marks incorrectly, investigate device scale, motion, kerf, or material behavior instead.

A Known Rectangle Reveals Where Scale Changed

Place a known-size rectangle outside the finished artwork. Do not resize the rectangle and artwork independently during the test.

For example, if the source rectangle is intended to be 100 mm wide, confirm that:

• The source application reports 100 mm.

• The exported SVG preserves the intended physical dimensions.

• The laser software reports 100 mm after import.

• A low-consequence mark or cut measures close to the intended size under the documented process conditions.

If both the artwork and rectangle import with the same ratio error, the cause is probably in units, document dimensions, DPI interpretation, or the import process. If only one object changes, inspect transforms, clipping, strokes, hidden objects, and object-level scaling.

Measure the imported bounding dimensions numerically. Visual size on the workspace is not evidence because zoom changes the display without changing the design.

Do not correct a known import error by memorizing a percentage. Find the conversion mismatch, correct the export or import convention, and verify the reference again.

Check SVG Units and ViewBox

Inspect the root SVG attributes and the final geometry after transforms. A viewBox defines an internal coordinate system; by itself, it does not guarantee that those units represent millimeters or inches.

Look for:

• Missing units on width or height.

• Pixel-based dimensions where a physical unit was intended.

• A viewBox whose aspect ratio differs from the physical dimensions.

• Nested transforms that scale or translate groups.

• Percentage-based dimensions.

• Responsive-export settings.

• Hidden layers or objects outside the intended artwork.

• Strokes that enlarge the reported bounds.

• Clipping masks that alter the visible and imported geometry.

Do not assume that a file is physically defined because it looks correct in a browser. A coherent SVG should carry enough information for the receiving application’s documented import behavior to produce the intended size.

Separate Document DPI From Laser Line Density

Document DPI and laser line density are different concepts. DPI assumptions can affect how unitless or pixel-based SVG coordinates become physical dimensions during import; laser line density affects how an operation is processed after the geometry has been imported.

Standardize the export from the design application:

• Set an explicit document or artboard size.

• Use explicit physical units where supported.

• Preserve or expand transforms consistently.

• Avoid scaling through copy and paste between applications.

• Retain the editable source and the exact SVG sent to production.

• Record the exporting application and version.

LightBurn documents two SVG import DPI choices: 96 DPI, identified as the default for Inkscape, and 72 DPI, identified as the default for Adobe Illustrator. It specifically advises trying the alternate setting when SVGs import at the wrong scale. LightBurn SVG import settings

Change that setting only after confirming the source application’s export convention. Do not change it globally and assume every SVG now imports correctly; files from different applications may use different conventions.

Before interpreting a placement problem as SVG scale, confirm the coordinate mode and job origin in Choose LightBurn Coordinates From the Job, Not Habit if that published URL is verified. A correctly sized SVG can still start from the wrong physical reference.

Control Stroke, Outline, and Clipping Effects

In LightBurn, compare the imported bounding dimensions with the known reference before applying any correction. Check whether the reported size includes:

• Stroke width.

• An outline generated from a stroke.

• Hidden or off-page objects.

• Clipping masks.

• Extra registration marks.

• A locked aspect ratio.

• A transform applied to only one group.

If a single global scale correction is required, identify its cause and document the convention. Do not create a production habit such as “always scale imported SVGs to 133 percent” unless the same export source, application version, and import configuration have been verified.

LightBurn can import SVG artwork, but the receiving application’s behavior does not guarantee that another laser program, browser, CAM package, or design editor will interpret the same file identically. LightBurn artwork import documentation

Run a Square-and-Circle Import Test

Use a low-consequence calibration file containing a known-size square, rectangle, and circle. The square checks X and Y dimensions; the circle helps reveal nonuniform scaling or later machine-motion problems.

Run the diagnostic in stages:

1. Measure the shapes in the source application.

2. Export the SVG without changing the reference objects.

3. Import it into the laser software.

4. Measure the imported dimensions numerically.

5. Check the preview for transforms, hidden objects, and operation assignment.

6. Mark or cut the test on suitable material using documented, conservative conditions.

7. Measure the physical result.

If the imported rectangle is wrong, fix the SVG or import convention first. If the imported rectangle is correct but the physical result is wrong, stretching the SVG would conceal a device-axis, motion, kerf, focus, or material issue.

A physical result can differ from the design dimension because a cut removes material or an engraving has a visible width. Separate geometric scale from kerf and mark appearance; do not use the outside edge of a cut as a pure test of file dimensions without accounting for the process.

Save an Application-Specific Export Preset

Archive the complete handoff:

• Source application and version.

• Document units and artboard size.

• Root SVG width, height, and viewBox.

• Transform and stroke treatment.

• Export preset.

• Exact SVG used for production.

• Imported bounding dimensions.

• Laser software and version.

• Device profile.

• Physical reference measurement.

• Any approved import correction and its scope.

A customer replacement file should repeat the size preflight even when the visual artwork looks similar. Similar appearance does not guarantee identical units, viewBox, transforms, text conversion, or hidden geometry.

Keep the editable source separate from the production export. If the export is repaired directly, record what changed and regenerate it from the master when practical.

A TwoTrees machine or accessory does not determine how an SVG’s units are interpreted. The TwoTrees TTS-20 Pro 20W laser engraver with TR2 Pro rotary risers may be relevant to a later hardware workflow, but its product page does not prove SVG compatibility, import scaling, rotary dimensions, or physical results for every software and configuration. Verify the exact machine, device profile, software, rotary setup, and current product details before purchase.

Keep Application-Specific Behavior in Its Own Page

The general diagnosis is portable: prove the physical size at each handoff. The exact fix is not always portable.

Applications may impose different assumptions about:

• SVG DPI.

• Unitless coordinates.

• viewBox.

• CSS.

• Strokes and outlines.

• Clipping masks.

• Text and fonts.

• Embedded metadata.

• Transform expansion.

• Import prompts or preferences.

Use this sequence to establish whether the SVG itself carries a coherent physical size, then follow the receiving application’s current documentation. Do not claim that one export preset behaves identically in LightBurn, Easel, a browser, and every CAM package.

Stop and consult the exact software documentation when the imported dimensions change despite explicit source units, a transform cannot be resolved, text or clipping changes the bounds, or the software’s import convention is unclear. Do not proceed to a valuable workpiece until the known reference imports at the intended size and the machine test confirms the separate device-scale assumptions.

References

1. LightBurn SVG import settings

2. LightBurn artwork import documentation

3. LightBurn coordinates and job origin

4. LightBurn beginner settings documentation

5. LightBurn overscanning documentation

6. TwoTrees TTS-20 Pro 20W laser engraver with TR2 Pro rotary risers