1、Three.js uses the right handed system and this means counter clockwise is default rotation.

2、i add a cube, and then it display as follows.

3、if i do a rotation as follows

```
cube.rotation.y += Math.PI / 6;
```

it displays as follows, which also is my expect

4、but if i do the rations as follows

```
cube.rotation.set(Math.PI, 0, Math.PI, "XYZ");
cube.rotation.y += Math.PI / 6;
```

it seems the direction of rotation changes to be clockwise;

you can also check the sandbox by: 骰子 (forked) - CodeSandbox

why does it happen, how can I know the direction exactly