Troubleshooting Guide

Common issues and solutions when working with Momentum.

FBX Retargeting: Incorrect Bind Pose

Problem: FBX shows correctly in fbx_viewer but fails to convert to GLB or produces wrong joint transforms.

Cause: Retargeting changes joint ordering, making skeleton incompatible with Momentum format.

Solution:

The core approach involves creating a joint name mapping between retargeted and expected joint names, then applying this mapping to reorder skeleton states before conversion.

1. Identify Joint Mapping: Compare joint names between retargeted FBX and expected character format
2. Apply Remapping: Use mapping to reorder skeleton states to match expected format
3. Convert to Transforms: Apply SkeletonState::compare() to validate and convert to joint transforms

Validation:

See test/io/io_fbx_test.cpp::Fbx_Retargeting_JointRemapping for a complete working example that:

• Simulates the joint reordering problem (demonstrates failure without remapping)
• Implements the remapping solution (demonstrates success with remapping)
• Validates that remapping significantly improves skeleton state accuracy

Tools:

• fbx_viewer: Visual validation of FBX files
• convert_model: Convert between FBX and GLB formats
• glb_viewer: Validate converted GLB results

Related Examples:

• Viewers Guide: Visual validation tools for different file formats
• Convert Model: Comprehensive FBX/GLB conversion examples