Choose a silhouette when you want the outside appearance of a 3D object from one direction. Choose a cross-section when you need the outlines where one plane passes through it, including any cavities. These outputs can look very different even when they come from the same STL file.
A LightBurn forum discussion about STL workflows illustrates the need to prepare two-dimensional vectors outside the laser software. For this small A1 Mini exercise, export one section or one silhouette. A stack of slices, a relief engraving and a photograph of the model are different projects.
Picture a hollow cup
Seen from above, a projected cup may give an outer footprint; visible overlapping geometry can obscure the distinction between the walls and empty space. A horizontal section through the cup's side wall contains an outer contour and an inner contour. A section below the cup's base may show no cavity at all.
That example is why the section plane belongs in the design record. Moving it changes the requested shape. Do not assume that every missing internal loop is an import failure; first inspect whether the plane actually intersects that feature.
| Desired A1 Mini artwork | Geometry to prepare | Check before export |
|---|---|---|
| Flat outline of an object | Projection from a chosen direction | No unintended overlapping silhouettes |
| Profile at one height | True planar cross-section | Plane location and internal loops |
| Visible model photograph | Raster image | This is not a dimensioned section |
| Small fit sample | Verified vector contours | Scale, closed paths and intended openings |
Inspect the vectors before assigning operations
Use a CAD tool that supports importing the model and exporting the required two-dimensional geometry. OpenSCAD's reference lists STL import and projection with its cut option; the correct model orientation and plane still need deliberate setup. This does not imply that LightBurn directly imports an STL as a ready-to-cut section.
Open the exported SVG or DXF and check one known measurement against the model. A reference-square scale check helps separate export units from geometric intent. Then examine every inner contour. For a cut part, an inner loop may become a hole; for a filled engraving, nested shapes may change what is darkened. Preview the intended operation before processing anything.
The A1 Mini lists a 120 × 130 mm work area. Use a small outline that fits the complete safe setup and supplier-approved sample stock. Being able to export a shape does not establish that its material, thickness or tiny details are practical to cut.
Why does my section include a hole I cannot see in the model view?
The plane may cross an internal cavity hidden by the model's outer surface. Inspect a sectional CAD view at that exact plane before removing the loop.
Can I center the exported shape by its bounding box?
Yes when a numerical center is the intended reference. An asymmetric outline may still look off-center; distinguish geometric centering from visual balance before shifting it for appearance.