I have a decimated model from ZBrush. Overall it looks nice, but on some parts I have overlapping vertices that cause shading problem like these.
The vertex is on top of another edge and If I edge slide it the problem is solved. My question is how can I detect all of these edges?
It will be much faster to instead use a Remesh modifier, which will preserve the shape of the object while giving you clean topology
If you really want to do this by hand, the long and painful way, enable the 3D Print Tools add-on that comes with Blender, it has a select overlapping feature. But seriously, just Remesh and save yourself a few hours