Armature and animation experiences: Blender 2.79 to Verge3D

Armature and animation experiences in 3D and 2D: Blender 2.79 to Verge3D (tested in version 2.11.1 – 2.12.0 pre2)
While preparing character animation with bones I have found some issues that complicate building an animator friendly rig that can produce reliable results for Verge3D (and probably WebGL in general). I don’t know whether this can be improved upon in the short term.
While still testing smaller movements of the characters the differences between Blender and Verge3D were not so clear but when testing the facial rig I discovered that results were becoming unreliable.
Differences between Blender and results in Verge3D became quite clear.

I have tried out all kind of different configurations to make the rigs (reasonably) animator friendly and make character animation in 3D and 2D work nicely in Verge3D.
Bone constraints:

• If only one constraint like Damped track constraint, copy transform constraint or IK constraint is applied things seem to work reliably.
• Stretch To constraint: gives unreliable results. (Probably too calculation intensive.) Also if it is the only constraint on the bone.
• When a bone has a constraint applied (even if only for 20%), readjusting the bone manually the adjustment will work in Blender but nut in Verge3D.
• When more constraints are applied to a bone, things start to get problematic. For instance:
  – The order of constraints is denied.
  – Percentages seem hard to calculate and give inconsistent results.

Linked objects:
To keep the file size as small as possible one uses linked duplicate objects as much as possible. In Blender linked objects can be animated separately from each other, but one has to unlink the animated ones (object and Data) to get it working reliably in Verge3D.

One rig I built gives reasonably reliable results in Verge3D but then I have to combine it with shape keys to fine tune it (which is possible in version 2.11.1). But keep in mind that the play animation of the rig (armature) puzzle has to be combined with the play animation of the object puzzle so I would prefer to work with the more adjustable rig and not rely on shape keys.
Unfortunately, a rig that is more adjustable and animator-friendly gives too unreliable results in Verge3D.

It would be really great if bone constraints applied in Blender would give one on one results in Verge3D and I hope that is doable.
I hope I expressed my findings clear enough and have attached a zip with some images that show some results quite clearly. I hope that helps.
Simone