Upload an IGES (.iges / .igs) file and download a tessellated STL mesh.
Input file
Everything runs in your browser — your files are never uploaded. STEP/IGES use the OpenCASCADE engine (a one-time ~7 MB download) and are tessellated into a mesh, so the result is a surface model, not editable CAD history.
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What is the IGES to STL?
IGES is a neutral CAD file format that preserves parametric surface and solid geometry with mathematical precision. STL is a triangulated mesh format that represents 3D models as collections of small triangles, making it the standard input for 3D printers and finite element analysis software. Converting IGES to STL tessellates the continuous surfaces into discrete triangle facets, a process called meshing or triangulation.
How it works
The converter reads the IGES file, parses its geometric entities (surfaces, solids, curves), and applies a meshing algorithm to divide the surfaces into triangles. The algorithm maintains surface normals (direction vectors) and checks for gaps or errors. The output STL file contains vertex coordinates and face connectivity in either ASCII (human-readable text) or binary (compressed) format. Resolution and triangle density are controlled by deviation tolerance—tighter tolerances produce more triangles and higher fidelity but larger file sizes.
Examples
Input
Result
Notes
IGES file (mechanical bracket with curves, 2.5 MB)
Binary STL file (48 MB) with 1.2 million triangles
High-resolution mesh suitable for 3D printing; smaller tolerance = more triangles
Import into your 3D printer software, CAM tool, or mesh editor and verify orientation and scale
Benefits
Enables 3D printing of CAD designs originally created in parametric modelers (SolidWorks, Fusion 360, AutoCAD)
Maintains design accuracy by controlling mesh density and deviation tolerance
Produces industry-standard STL format compatible with all slicers, printers, and simulation software
Eliminates proprietary lock-in—convert vendor-specific CAD to portable, universal mesh geometry
Faster iteration in manufacturing workflows: edit in IGES, convert to STL, print and validate
Tips & common mistakes
Common mistakes
Forgetting to scale units—IGES may be in inches but your printer expects millimeters; always verify and rescale in your slicing software
Using excessive mesh density (very tight tolerance) on large files, creating multi-gigabyte STLs that crash slicers or burn processing time
Ignoring hollow or thin-walled geometry—some IGES files contain surfaces only, not solid volumes; inspect the STL in a mesh viewer to confirm it is manifold
Assuming the conversion is lossless—curved surfaces are approximated by triangles; inspect edges and rounded features for visual quality before printing
Tips
For 3D printing, use a tolerance of 0.05–0.1 mm; for visualization, 0.5–1 mm is often sufficient and saves disk space
Always open the converted STL in a free tool like Meshmixer, MeshLab, or your slicer software to inspect for errors, inverted normals, or gaps before committing to print
If your IGES file contains multiple bodies, ensure they are merged or assembled in the source before conversion—some converters will export only the active part
Keep the original IGES file; STL conversion is one-way, so if you need further parametric edits, return to the original CAD model
Frequently asked questions
What is the difference between IGES and STL?
IGES stores mathematical surface and solid definitions with exact curves, allowing future editing. STL is a triangulated mesh approximation suitable for 3D printing and visualization, but not for parametric modification. IGES is parametric; STL is a dumb mesh.
Can I convert STL back to IGES?
Not directly with full fidelity. Reverse-engineering (surface reconstruction) from mesh to parametric CAD is possible but expensive and imperfect. It's best to keep the original IGES and regenerate STL as needed.
Why is my converted STL file so large?
High mesh density (tight tolerance) creates millions of triangles. Reduce the tolerance setting during conversion or use mesh optimization tools like Meshmixer to decimate the triangle count after conversion.
Does the conversion preserve color or material properties?
Basic STL does not; it stores only geometry (vertex coordinates and triangles). Some CAD systems export colored or multi-body STL variants, but standard STL is monochrome geometry only. Texture and appearance must be handled separately in 3D printing or rendering software.
What tolerance should I use for 3D printing?
A deviation of 0.05–0.15 mm works for most FDM and resin printers. Tighter tolerances (0.01 mm) are rarely necessary and inflate file size; looser (0.5 mm) save space but may make curved details blocky.
Can I convert IGES assemblies with multiple parts?
Yes, but most converters output a single merged STL. If you need each part as a separate STL, export parts individually from the IGES or use a CAD tool to split the assembly before conversion.