Why does subtracting weights add weights to other parts of the mesh? So my problem is that I'm trying to subtract weight, and it works in some areas, but in other areas of the mesh it just adds unsubtractable weight to the mesh. Is this a bug, or is this something that I'm just doing horribly wrong? The mesh is not originally mine, and I'm pretty new to blender.




Here's the file:
Turn off "Auto Normalize" and it'll work as expected.

What normalizing means:

Let's say we had a vertex group with four vertices that have a weight value of 0.1, 0.3, 0.45 and 0.7.
Normalizing these values would mean that every weight is scaled up so that the highest value is 1. To achieve that, divide 1 with the highest value and multiply your other weight values with the result.
In our case this would mean 1 divided by 0.7 = 1,4285714286.

If we apply this equation on our values, we get 0.14, 0.43, 0.64 and finally 1. 

(Every value rounded to two decimal places.)