@acelepage
Hello,
Depending on what you read about the BVH file format, the article may describe the conversion of the rotations through full matrix multiplications. What I mean is, you will be told to calculate the rotations down the hierarchy chain. I haven't looked at the rotations in a BVH file for a little while now but if I recall correctly, all of the rotations are local - that's usually why an article that describes the conversion talks about the matrix multiplication. The article assumes you have to manage your own hierarchy so that you can transform the rotations into world space.
In DBPro, the limb hierarchy already exists. If the limbs are linked in Parent child relationships, then each rotation of a limb is local but the full motion of the parent+child rotation is global. So, if your limbs are linked properly, you should only have to use the rotations specified for each limb from the BVH file and not have to multiply the rotation matrices together.
The other thing to consider is the rotation order of the axes in the BVH file and which axis points up. Again, I haven't played with BVH files for a little while so I can't quite remember, but I think this information is included right before or within the ROOT definition.
Be aware that different programs may use modified versions of BVH files so one BVH file may not be setup (rotation wise, axis wise, and the inclusion of standard limbs/groups) as another so you must check for these things in your conversion program.
Enjoy your day.
