What is a 123DX file?
A .123DX file is a 123D Design Model File. Autodesk created this format for their Autodesk 123D Design software. The file holds 3D models, geometry, and design settings used for 3D printing and computer-aided design (CAD).
How to open 123DX files?
Autodesk 123D Design is discontinued, which makes opening these files difficult on modern systems. However, you can import .123DX files directly into Autodesk Fusion to edit the 3D models.
Because a .123DX file uses the standard ZIP compression format, you can also inspect its contents manually. You can rename the file extension from .123DX to .ZIP and extract it using archive tools like 7-Zip or WinRAR.
Best practices and troubleshooting
If you need to 3D print a design stored in this format, you must convert it first. Import the file into a compatible CAD program and export the geometry as an .STL or .OBJ file. If you receive a .123DX file from an unknown source, inspect the extracted ZIP contents to ensure it only contains safe design data.
Summary
viewer.online/123dx analyzes .123DX files to identify their exact format and creator software, shows which programs can open the file, and usually previews it. Because .123DX files use the known ZIP format, viewer.online/123dx can safely open and display them online, eliminating compatibility problems.