Clockwise or counter-clockwise loading animation

Question

Is there any rule for using CW or CCW loading animation?

Does CCW animation means "slow" or "rollback" or something? Or maybe CW direction means going forward, straight direction etc?

UPDATE: due to Renaud's answer I'll mention - I want to display spinner animation.

Answer 1

I would say that it depends on what you are showing on the loading animation :

if you just want to show that something is loading without any duration information, a clockwise will tell the user he just have to wait.

but if you actually display an information about how long the loading will last (much better) you can use 1 round of counter-clockwise like a countdown.

Answer 2

I like the Chrome way, where uploading/sending is a ccw-circle and loading is a cw-circle. I don't believe there is any rule about it though.... just keep it consistent.