Frequently Asked Questions

What file formats do you support?

We support the most common 3D file formats you'll encounter: STL, OBJ, PLY, 3MF, STEP/STP, GLTF, and GLB. These cover everything from basic 3D printing (STL) to professional CAD work (STEP) to web applications (GLTF).

If you need a format that's not listed, let us know. We're always adding support for new formats based on user requests.

Is there a file size limit?

Free users can upload files up to 20MB each. Pro users get 500MB per file, which is more than enough for even complex industrial models.

If your file is larger than the limit, try using a more efficient format first. For example, binary STL files are much smaller than ASCII STL files with the same geometry.

How long does conversion take?

Most conversions finish in under 10 seconds. Complex files or certain format combinations (like STL to STEP) can take longer because the software has to do more mathematical work.

If a conversion is taking more than a minute, there might be an issue with your file. Try refreshing the page and uploading again.

My file won't upload or convert

First, check that your file is actually in the format you think it is. Just because a file has a .stl extension doesn't mean it's a valid STL file. Try opening it in other software to verify it's not corrupted.

Some common issues:

• File is password-protected or encrypted
• File extension doesn't match the actual format
• File was corrupted during download
• File uses a non-standard variant of the format

The converted file looks wrong

Scale issues are the most common problem. Different software uses different units (millimeters, inches, meters), and this can make your model appear tiny or enormous after conversion.

Other things to check:

• Units and scale in your target software
• Whether faces are flipped inside-out
• Missing textures or materials (expected when converting to simpler formats)
• Mesh resolution - some conversions approximate curved surfaces

Colors and textures disappeared

This is normal when converting to simpler formats. STL files don't support colors at all. If you need to preserve color information, use formats like OBJ, 3MF, or GLTF.

Remember that even when a format supports colors, the target software might not display them. Your 3D printer slicer might show a colorful OBJ file in gray because it's designed for single-material printing.

Should I use STL or 3MF for 3D printing?

If your slicer and printer support 3MF, use it. 3MF files are smaller, support multiple materials and colors, and can store print settings. It's the future of 3D printing file formats.

Stick with STL if you're using older software, sharing files with others who might not have 3MF support, or if you just want maximum compatibility.

My 3D printed model came out wrong

File conversion rarely causes printing problems - it's usually a slicer or printer issue. But here are a few file-related things to check:

• Model scale is correct (check units)
• No mesh errors like holes or non-manifold edges
• Wall thickness is appropriate for your printer
• Model orientation makes sense for printing

Can I convert G-code files?

G-code is fundamentally different from mesh files. It's a list of instructions for your 3D printer, not a description of 3D geometry. Converting G-code to STL is possible but limited - you'll get an approximation of what the printer would create, not the original model.

If you need to modify a model, try to get the original STL or 3MF file instead of working from G-code.

Why does STEP to STL conversion take so long?

STEP files contain precise mathematical surfaces that need to be converted into triangle meshes. This involves a lot of computation to approximate curves with flat triangles while maintaining accuracy.

The more complex your model, the longer it takes. Simple geometric shapes convert quickly, but organic shapes or models with many small features take more processing time.

Can I convert STL back to STEP for editing?

Technically yes, but don't expect perfect results. STL to STEP conversion is reverse engineering - the software tries to guess what the original parametric model looked like based on triangle mesh data.

This works reasonably well for simple geometric shapes but struggles with organic forms or models with fine details. For serious CAD work, always try to work from the original parametric files when possible.

GLTF vs GLB - what's the difference?

GLTF is the "source code" version - human-readable JSON with separate files for textures and binary data. GLB packages everything into one binary file, making it more efficient for web delivery.

Use GLTF during development when you need to inspect or modify the file structure. Use GLB for production when you want fast loading and simple deployment.

Why is my GLTF file huge compared to the original?

GLTF includes a lot of metadata for rendering - materials, lighting information, scene graphs. If you're converting from a simple format like STL, all this extra information gets added with default values.

For web use, this is usually worth it because GLTF renders much more efficiently than other formats. The extra download time is offset by faster rendering performance.

The conversion failed with an error message

Most errors are caused by problematic source files. Try these steps:

• Verify the file isn't corrupted by opening it in appropriate software
• Try re-exporting from your original software with different settings
• Check if the file uses an unusual variant of the format
• Try converting to an intermediate format first, then to your target format

Can I convert multiple files at once?

Yes! You can upload up to 3 files at once with a free account, or up to 50 files with a Pro account. Each file is converted individually - we don't combine multiple files into one output.

If you need to combine multiple 3D files into one, you'll need to do that in 3D modeling software before converting.