LuminaMesh – Free STEP to STL & 3MF Converter, Plus STL Wall Thickener
LuminaMesh is a free, browser-based toolkit for 3D printing and CAD file conversion. It converts
STEP and STP CAD files to STL or 3MF format,
keeping multi-body assemblies separate so you can preview and download individual parts on their
own. It also includes a full STL wall thickener and thin wall repair
tool for 3D printing.
STEP / STP to STL & 3MF Converter
- STEP to STL converter — convert STEP and STP CAD files to print-ready STL, entirely in your browser
- STEP to 3MF converter — export multi-body assemblies as one structured 3MF file, with each part kept separate
- Per-part preview and download — inspect each solid body individually and export only the parts you need
- No upload required — conversion runs locally using a WebAssembly CAD geometry kernel
STL Wall Thickener & Thin Wall Repair
- STL thin wall detection — scan your model and identify every face below your minimum wall thickness threshold
- STL wall thickener — automatically grow thin walls outward using normal-based vertex dilation
- Wall thickness heatmap — visualize STL wall thickness with a live 3D color gradient (green = thick, red = thin)
- STL thin wall repair — fix thin walls and blend with Laplacian smoothing for clean geometry
- Print bed visualizer — check fit for Ender 3, Prusa MK4, Bambu Lab P1S/X1C, or custom build volumes
- Filament cost estimator — estimate weight and cost for PLA, PETG, ABS, and TPU at any infill
Who is this for?
Anyone who received a STEP file without access to the original CAD software and
needs a print-ready STL or 3MF out of it — especially when the file is a multi-part assembly and
only some components are needed. Also anyone who has had a slicer warn about thin walls
in an STL, or whose 3D prints came out fragile because of walls too thin to print
reliably.
Guides
JavaScript is required to use LuminaMesh. Please enable JavaScript in your browser.