A few solutions: Bone Heat Weighting error in Blender

Here are a few solutions that might help you fix the Bone Heat Weighting error in Blender. I&seen only a couple of them posted online so I wanted to demonstrate a couple of alternatives. Timestamps with different methods: 00:44 - Merge vertices o clean up the mesh. 01:17 - Use the Decimate modifier to reduce the polygon count. 02:42 - Increase the scale of the mesh + rig. 04:25 - Transfer weights from a placeholder object to the original mesh. One other method I forgot to cover is to enable Blender&built-in 3D-Print Toolbox add-on and click the "Make manifold" button inside its panel. For Blender versions 2.8 and up. I hope this helps.