What is a CTM file?
A .CTM file is primarily an OpenCTM compressed 3D triangle mesh. This file format stores 3D model data efficiently and reduces file size without losing geometry quality.
However, the .CTM extension has multiple possible meanings. It can be a Star Wars Republic Commando Map File created by LucasArts, an Unreal Engine map package file, a Citra 3DS Emulator movie recording, or a Reallusion CrazyTalk model file. Developers also use it for Minecraft custom translations, EU Intellectual Property Office data, and Broadcom Bluetooth installer configurations.
How to open CTM files?
Because a .CTM file can serve many different purposes, you must know its exact format before you open it. You can open OpenCTM 3D models with MeshLab or Blender using community plugins. Game map files require specific map editors, such as UnrealEd for Unreal Tournament maps. Emulator recordings only work inside the Citra software.
Software and tools
If you work with 3D meshes, the OpenCTM project provides command-line tools like `ctmconv` to convert .CTM files into standard formats like .OBJ or .STL. For text-based .CTM files, such as custom translation memory files, a code editor like Notepad++ allows you to view the raw text.
Identify and view CTM files online
viewer.online/ctm can analyze .CTM files to identify the exact format and creator software, inspect the file structure, extract readable text, and check whether an online preview is available.
Summary
Since the .CTM extension is shared across 3D software, game engines, and text applications, viewer.online/ctm is useful for identifying, inspecting, and understanding .CTM files without installing software or dealing with compatibility problems.