123d

.123d — Autodesk 123D Design File

Autodesk · 2012

Developer

Autodesk

Key Features

Stores parametric 3D models.
Supports feature-based design history.
Native format for Autodesk 123D Design.
Suitable for beginners and hobbyists.

Best For

Beginner 3D modeling projects.
Creating printable models quickly.
Parametric design work within 123D Design.
Projects where feature history is important.

Less Ideal For

Complex, professional CAD work.
Interoperability with other advanced 3D software.
Animation or rendering intensive projects.
Long-term archival without conversion.

Common Use Cases

Creating simple 3D objects for 3D printing.
Designing custom parts for projects.
Educational purposes for learning 3D modeling.
Storing early versions of 3D designs.

How to Open It

The primary way to open .123d files was with Autodesk's 123D Design software, which is no longer available for download.
Some users report success opening them with Autodesk Fusion 360 by importing the file.
Conversion to a more common format like STL or OBJ using compatible software might be necessary.
Explore 3D viewers or converters that support older Autodesk proprietary formats.

What is a .123d file?

The .123d file format is native to Autodesk's 123D Design software, a user-friendly application aimed at hobbyists and beginners for creating 3D models. It stores parametric and feature-based 3D designs, allowing for easy modification and manipulation of models. While the 123D software suite has been retired, these files still represent a common format for storing simple to moderately complex 3D designs from that era. They are useful for educational purposes or for continuing projects started with the original software.

Programs That Open .123d Files

Platform	Program
Windows	Autodesk Fusion 360	Paid	Official
macOS	Autodesk Fusion 360	Paid	Official

How to Convert .123d Files

Format	Method
.STL	Autodesk Fusion 360, Online Converters
.OBJ	Autodesk Fusion 360, Online Converters

Common Problems with .123d Files

⚠️ Autodesk 123D Design software is discontinued and no longer officially supported.

Attempt to open the file in Autodesk Fusion 360 or use a file converter to change it to a more widely supported 3D format like STL or OBJ.

⚠️ Limited compatibility with other 3D modeling software.

Export or convert the .123d file to a standard format such as STEP, IGES, STL, or OBJ for better interoperability.

Frequently Asked Questions

Can I still use Autodesk 123D Design?▼

The 123D Design software has been retired by Autodesk and is no longer available for download or official support. You might find older versions online, but compatibility and security are not guaranteed.

What is the best way to open a .123d file today?▼

Autodesk Fusion 360 is the most likely successor application capable of opening and working with .123d files. Alternatively, convert it to a common 3D format like STL.

Is .123d a good format for 3D printing?▼

Yes, .123d files can be converted to formats like STL or OBJ, which are widely used for 3D printing. The original software was designed with hobbyist 3D printing in mind.

Technical Details

The .123d format is a binary file that contains geometric data, assembly information, and potentially feature history for parametric modeling. It is specifically designed to store the state of a model within the 123D Design environment, enabling non-destructive editing through its feature tree.

Did You Know?

The 123D Design software was part of a larger suite of Autodesk applications aimed at making 3D creation accessible to a wider audience.

While the software is gone, the legacy of .123d files persists for those who used it for projects or continue to find them.

Security Information

As a proprietary binary format, .123d files can potentially contain malicious code if downloaded from untrusted sources, though this is less common for 3D modeling files than executable files. Always scan files from unknown origins.