In a difficult to predict/diagnose way, nested DOFs often appear perfect in Blender, but then are rotated and displaced when exported to BML, typically by multiples of 90 degrees. The issue appears to be related to parenting. Sometimes, adding an additional Empty object between one of the DOFs and its child solves the issue. Sometimes removing that empty and parenting objects directly to the DOF fixes the export problem. The behavior is unpredictable but usually solvable by some combination of the above.
The issue is compounded by existing complexities with transformations in Blender - but good practices of applying scale (and rotation where appropriate) still do not prevent this bug.
In a difficult to predict/diagnose way, nested DOFs often appear perfect in Blender, but then are rotated and displaced when exported to BML, typically by multiples of 90 degrees. The issue appears to be related to parenting. Sometimes, adding an additional Empty object between one of the DOFs and its child solves the issue. Sometimes removing that empty and parenting objects directly to the DOF fixes the export problem. The behavior is unpredictable but usually solvable by some combination of the above.
The issue is compounded by existing complexities with transformations in Blender - but good practices of applying scale (and rotation where appropriate) still do not prevent this bug.