Bone heat failure is to rigging what ‘missing texture’ is to baking. Everything on this appears perfect, but it is quite large. I did this and it worked. Basically I scaled it down 10%, applied scales, auto weighted it, and then scaled it all back up 10 times, and applied scales…
1)select both object and armature
2) S .1
3)Ctrl a (rot and scale) ctrl a (location)
4) select object, select armature, ctrl p auto weithgs
5) S 10
^) ctrl a (rot and scale) ctrl a (location)
When the mesh has 2 outside layers blender will not know what bone it is for. the things on the arms can you make them a separate object and parent them to a bone? The collar around the neck is 2 layers thick will need painting or armatures inside. the things on the legs will freak out Blender can you make them separate objects?
edit 2 answers before i could post mine.
I literally signed up this site to thank you.
Tried many things and made my models again and again but nothing worked, your solution worked perfectly. Thank you so much mate happy new year!