An OBJ file can get in the way when the slicer expects STL. STL is the standard most 3D printers accept, and it is also common in rapid prototyping and computer-aided manufacturing. A lot of CAD software can export STL, but not every modeling program does, so a converter is still useful when a model arrives in the wrong format. I ran into that recently with a downloaded OBJ. A few online converters were available, but they were not pleasant to use. i3DConverter opened with an error prompt, yet it still converted the file, and Cura read the result normally. AccuTrans 3D was the better tool in my case. It offers a 30-day trial and can be downloaded from Micromouse. It is built to preserve mesh information such as position and rotation, and its batch mode can convert a mixed list of 3D formats into STL. I also kept a backup of the converted file on an h5ai file server. Both desktop tools are worth keeping around, and the list below covers 12 more options, from small online utilities to full conversion programs.
1. AccuTrans 3D
AccuTrans 3D focuses on accurate translation of 3D geometry. One advantage is that it keeps mesh information such as position and rotation. Batch mode also lets you turn a mixed list of 3D file formats into STL. The software is available as a free trial from Micromouse and currently runs only on Windows. It supports more than 30 file types, including MA, X3D, and XYZ.
2. 3D Transform
3D Transform is a free online tool for turning 3D models into STL. You can upload files up to 6 MB. The service says you keep the intellectual property of uploaded files or must have the right to use them, but it does not guarantee that every 3D file will convert successfully. Supported formats include IGS, IGES, STP, STEP, BREP, 3DS, ASE, DXF, STLA, STLB, WRL, IV, OBJ, SWV, and GMOD.
3. SwiftConverter
SwiftConverter is a free online converter for images, documents, audio, video, and 3D files. It converts 3D models to STL and other common formats. The dashboard is straightforward, and uploads can be as large as 100 MB. It handles more than 25 file types, including 3DS, FBX, Blender, OBJ, DXF, LWO, and PLY.
4. i3DConverter
i3DConverter is a desktop program that can convert almost any 3D file format. It works on Mac and Linux. A lifetime license costs $50, and a free trial is available. The supported format list is unusually broad, with more than 760 file types, including CAD, OBJ, PLG, and XML. In my test, a portable copy displayed an error when opening the file but could still perform the conversion, and Cura loaded the resulting STL.
5. Online CAD File Converter
Online CAD File Converter does one job: it turns 3D models into STL in a few seconds. There are three packages: Basic at €1 per conversion, Plus at €10 for 10 conversions, and Pro at €40 for 50 conversions. After payment you receive a coupon that can be used for files up to 100 MB. A trial version is also available. The company offers a refund if you are unhappy with the result. It supports 25 file types, including 3DS, DWG, SKP, SLDPRT, and SLDASM.
6. Meshconvert
Meshconvert is a free online converter for mesh files up to 15 MB. Besides STL, it can output DAE, OBJ, and PLY. The service notes that it does not guarantee every feature of the input format will survive conversion. It supports more than 35 file types, including 3DS, DXF, BLEND, and XML.
7. Makexyz
Makexyz is known as a platform that connects people with local 3D printers and designers, and it also offers a free online converter. The catch is that this converter only handles 3DS to STL. You can try it on the Makexyz website. Supported input format: 3DS.
8. Greentoken
Greentoken was developed by German programmer Alexander Gessler. It is a free online 3D model converter that supports a range of formats and can output STL as well as STLB, Collada, OBJ, 3DS, PLY, and JSON. You can upload up to five files with a total size of 50 MB. It supports more than 30 formats, including 3DS, FBX, Blender, OBJ, DXF, LWO, STL, and PLY.
9. Materialise Cloud
Materialise is a major name in 3D printing software and services, and Materialise Cloud is its 3D printing toolbox. Beyond repairing and designing models, it can convert 3D files to STL. After registering, the first 10 files can be uploaded for free. After that, you can choose from three package options to upload more models. Supported formats include OBJ, 3DM, 3DS, 3MF, DAE, DXF, FBX, IGES, IGS, PLY, SKP, SLC, VDAFS, VDA, VRML, WRL, ZCP, and ZPR.
10. Bear File Converter Online
Bear File Converter Online is a free tool for images, video, audio, ebooks, documents, and 3D files. It accepts 3D models below 50 MB. Conversion can take a little time, but the interface is simple. It supports more than 35 file types, including ASE, DXF, and OBJ.
11. Yobi3D
Yobi3D is a 3D model search engine that lets you find models online with keyword searches. It also provides a free tool for converting 3D files up to 40 MB. Depending on the complexity of the model, the converted file may take a while to download. Supported formats include 3DS, BLEND, DAE, DWG, DXF, FBX, MA, MAX, MB, and OBJ.
12. Spin 3D Mesh Converter
Spin 3D Mesh Converter is an easy-to-use 3D mesh conversion program. It can convert files with one click, and its batch mode can process multiple files in minutes. It also lets you share 3D models with others in various formats. The software is Windows-only and is available as a free download from NCH Software. It supports more than 40 file types, including 3DP, 3DS, 3MF, OBJ, and PLY.