Migrate older version projects to Cubism 4 SDK


In this page, we will explain the advantages and disadvantages of migrating from the previous versions of Cubism SDK, Cubism 3 SDK and Cubism 2.1 SDK, as well as a simple flow image for the release of Cubism 4 SDK.

Before we begin, the handling of Cubism 3 SDK and Cubism 2.1 SDK after the release of Cubism 4 SDK is as follows.

  • New downloads will be stopped and no further updates will be made
  • No new features will be supported in the future
  • Defects are targeted individually and corrected only when a defect is reported


Migrating from 3 SDK to 4 SDK

The following are advantages and disadvantages for users of Cubism 3 SDK when migrating to Cubism 4 SDK.


  • New functionality is available (mask inversion)* Coma hitting function and extended interpolation can be used for embedded data exported by Cubism 3 or equivalent.
  • Models created with Cubism 3 Editor can be used without modification (backward compatibility)


  • None

Flow Image

The structure of Cubism 4 SDK is basically unchanged from Cubism 3 SDK. When migrating SDKs, after replacement, you can use them by rebuilding them if necessary.
When using the sample code as it is at the time of SDK migration to verify operation, the third-party libraries used in the sample code may have been updated or the directory structure may have been changed.
Please refer to the README and CHANGELOG for each platform of Cubism 4 SDK for details.


Migrating from 2.1 SDK to 4 SDKs

The following are advantages and disadvantages for users of the Cubism 2.1 SDK when migrating to the Cubism 4 SDK.


  • Improved maintainability by extending the scope of SDK source release
  • Many functions not implemented in 2.1 are implemented, enabling even richer expression
  • Because all parts other than the Core are open source, almost all customization, including the renderer part, can be done freely
    * Please note that this requires acceptance of the Live2D Opensoftware License.


  • High cost of transition
    • Need to replace a complete set of SDKs
    • Data for model incorporation needs to be re-written to the latest format
      Depending on the model, there may be work to be done to correct the data before exporting it back for incorporation. The contents are listed in the flow image.

Flow Image

When migrating from Cubism 2.1 SDK to Cubism 4 SDK, be sure to read .cmox and .canx files in Cubism 4 Editor and export them to Cubism 4 SDK built-in data.

In addition to replacing the SDK and model data, there may be other work to be done to make the geometry and operation compatible.
The following is a description of possible work and how to respond.


If the deformation and drawing results of the migrated model are different

The model will need to be adjusted.
Load the .cmox to be migrated in the Cubism 4 Editor and adjust the deformation results.
After adjustment is complete, export the .moc3 file and check the display on an actual device equipped with Cubism 4 SDK.


About mtn files (motion files) used with Cubism 2.1 SDK

Cubism 4 SDK does not support .mtn. However, since Cubism 4 Editor can read .canx files, it can be handled by exporting the loaded .canx to motion3.json.
However, the motion curve cannot be completely reproduced, and changes in the values on the timeline are processed to create a curve with approximate values.


Support for Physics Calculations

Physics operations used in Cubism 2.1 cannot be used in Cubism 4 SDK without modification.
For models using Cubism 2.1-created physics, please set physics again in the Editor.


About parameter IDs

The IDs of parameters specified in Cubism SDK for breathing, eye tracking, etc. have been changed to Cubism 4 specifications.
When migrating models used in Cubism 2.1, please convert them to Cubism 4 specifications at the time of export.

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