Convert MDD to BVH

Understanding mdd and bvh file formats

MDD (Mesh Deformation Data) is a file format used to store vertex animation data for 3D meshes. It is commonly used in 3D animation pipelines to transfer mesh deformation (such as facial expressions or cloth movement) between different software packages. MDD files contain per-frame vertex positions, making them ideal for complex mesh animations.

BVH (Biovision Hierarchy) is a file format designed for storing motion capture data. It describes the hierarchical structure of a skeleton and the motion of each joint over time. BVH files are widely used in character animation, especially for humanoid figures, as they provide both the skeleton structure and the animation data.

Why convert mdd to bvh?

Converting MDD to BVH is not a typical workflow, as MDD stores mesh deformation and BVH stores skeletal animation. However, in some cases, you may want to approximate mesh animation with a skeleton-based animation for compatibility with game engines or motion capture systems. This process usually involves retargeting or baking mesh deformations onto a skeleton.

How to convert mdd to bvh

Direct conversion from MDD to BVH is not natively supported by most software, as the data types are fundamentally different. However, you can use 3D animation software to import the MDD file, apply it to a mesh, and then use rigging and motion capture tools to transfer the animation to a skeleton. Once the animation is on the skeleton, you can export it as a BVH file.

Recommended software for mdd to bvh conversion

• Blender: Blender is a powerful, free 3D software that supports both MDD and BVH formats through add-ons. You can import your mesh and MDD file, rig the mesh with an armature, use tools like mesh-to-bones baking (such as the MDD Add-on), and then export the animation as BVH using File → Export → Motion Capture (.bvh).
• Autodesk Maya: Maya, with the help of plugins like Red9 or custom scripts, can import MDD files, retarget the animation to a skeleton, and export as BVH via File → Export All → BVH.

Step-by-step conversion using Blender

1. Install the MDD import add-on in Blender.
2. Import your mesh and apply the MDD animation.
3. Rig the mesh with an armature (skeleton).
4. Use mesh-to-bones baking tools to transfer the animation from the mesh to the skeleton.
5. Export the skeleton animation as BVH via File → Export → Motion Capture (.bvh).

Tips and considerations

• Manual adjustment may be required to ensure the skeleton matches the mesh movement.
• Some loss of detail may occur, as mesh deformations are more complex than skeletal animation.
• Always check the exported BVH in a viewer to ensure the animation quality.