Raycast strange behaviour

Questions
1

Hi,
I just created a simple environment with 2 spheres and making raycast between each other. From A to B I get intersection but not from B to A, why this can happen ?

I’m checking directions , … and everything seems fine but no intersection happen from one of the sides
here a fiddle Threejs Boilerplate - JSFiddle - Code Playground

Thanks in advance

2

By performing some more test, I was adding scalar value to the positions of the object so they get out of “perfect positions” and then it works

But it’s still quite strange to understand why this behaviour, seems like the issue was when the origin of the ray and the direction of the ray have the same value (0,1,0)

Would be great if someone can put some light