UVs on Blender and Substance Painter are different I have this problem with UVs,

In blender my UVs look like this:


For example Substance Painter UV looks like this:



There are weird spiky bits in the bottom right where as in Blender's UVs there aren't.

What is the problem? Can someone explain?
If you want to export your model to other softwares (like substance painter), you have to apply your modifier first.

When applied, you can see that your UV are broken, you have to re-unwrap.



Little tips after seeing your .blend : when you used mirror modifier, be sure to have all your half-mesh on the same side. This will prevent arrival of weird artefacts or bugs.