VRM4U Documentation

VRM4U supports the following environments:

• Unreal Engine Versions: UE5.4 to 5.0, and UE4.27 to UE4.20. (Note: UE4.19 is supported but materials will not be generated).
• Platforms:
  • Windows
  • Mac (requires project build)
  • Mobile (Android, iOS)
• Rendering:
  • Supports both Forward and Deferred shading.
  • Mobile support is available via BoneMap reduction to allow SkeletalMesh usage in the official UE4 editor.

VRM4U provides automated processing for VRM assets:

Animation and Rigging

• Automatically generates bones, blendshapes, swing bones, collisions, and humanoid rigs.
• Allows switching the swing bone type between PhysicsAsset and VRMSpringBone.

Materials

• Provides MToon simulated materials without requiring post-processing.

VRM4U provides several automated features for VRM integration in Unreal Engine:

• Animation: Automatically generates bones, Morphtarget/BlendShapeGroups, and spring bones/collisions. You can choose between VRMSpringBone or PhysicsAsset for spring bone behavior. It also generates a Humanoid RIG for easy animation retargeting.
• Materials: Implements materials that reproduce the MToon look, including shadow color specification, outline color/thickness adjustment, and MatCap. It allows characters to be rendered within existing PBR backgrounds without requiring post-processing.
• Mobile Optimization: Uses BoneMap reduction to enable SkeletalMesh usage on mobile via the official UE4 editor.

To use VRM4U, ensure your environment meets the following requirements:

• Unreal Engine Version: UE4.20 through UE4.27.
• Supported Platforms: Windows, Android, iOS, and Mac (via ProjectBuild).
• Mobile Support: Supports both Forward and Deferred rendering. It utilizes BoneMap reduction to enable VRM usage on mobile via the vanilla UE4 Editor.

VRM4U is a runtime VRM loader for Unreal Engine 4 (UE4). It allows you to import VRM files and load models at runtime.

To use it, simply drag and drop a VRM file into the Unreal Engine editor.

To install VRM4U, download the plugin version compatible with your Unreal Engine version from the releases page. Extract the contents into a Plugins folder located in the same directory as your .uproject file.

Your project structure should look like this:

+ MyProject
  - MyProject.uproject
  - Plugins
    - VRM4U
      - VRM4U.uplugin

While Windows users can use the pre-built binaries, other platforms may require manual source handling:

• Mac: Requires obtaining and building the custom version of assimp.
• Mobile: Standard usage requires no extra steps. However, if you are using Runtime Loading, you must obtain and build the custom version of assimp.

The custom assimp source can be found at: https://github.com/ruyo/assimp

The sample map is located at: VRM4UContent/Maps/VRM4U_sample.umap

If the map does not appear in your Content Browser, check your project settings/folder visibility.