Are there cases whereby auto weights won't work "no matter what"? I have a 70,000 poly mesh of a winged creature that i've rigged up as best i can (intermediate artist here). I don't get it. I've triple checked everything - having made sure the mesh is 'closed' (no holes), removed all double verts, cleared the scale and rotation values to zero (mesh at perfect center facing the front), left and right sides are symmetrical, bones point in the correct axis direction (as far as i can tell anyway), naming syntax is all correct, etc, and my armature still won't bind to the mesh after applying automatic weights. I've tried Rigify, the Auto Rig Pro addon, and have manually created my own armature  and still no joy (haven't tried BlenRig, but why should it be any diff). So, my question is: Are there cases whereby automatic weights (ctrl+p) won't work no matter what you do, if for example, the poly count is say over 50 - 70k?  If the mesh is fairly complex (a non-typical biped with dragon wings), will the auto weight procedure fail even if everything is 'in order'? And if this is the case, what do you do when the bind fails? ..skin everything manually?? That would take forever, seeing that blender doesn't have mirroring when you weight paint. I think Maya has mirrored weight painting so that would no doubt save some time, but who wants to go there, right?!  Thanks for whatever info you can offer on this!! (i've attached a screen grab of the bones &amp; front view and will upload the .blend file if needed, but it's info on 'what' i need to do (procedure) at this point more than on 'how' i need to do it. I'm using v2.79). Thanks again..

Tim
Here's the blend file link:
There is non manifold mesh in your model. Go to edit mode, make sure you are in vertex select mode, deselect all, from the menu select->select all by trait->non manifold (shift-ctrl-alt-m). There's a lot of geometry in the head, lips, teeth, nose etc. If the model is not going to have complex facial animation or speech, delete all that wasted geometry inside the head. The other areas you will have to just attack piece by piece. Having selected the non manifold mesh you can ctrl-numpad+ a couple of times to select the surrounding verts, ctrl-i to select inverse and 'h' to hide most of the mesh. This will clear the field for you to work on isolated parts.