How do I render my animation with a transparent background using Arnold and 3Ds Max

[B.Creative]

Hi,

I have an object that I will animate and then render with transparent background. I use 3Ds Max and Arnold renderer. The animation is supposed to be used in Adobe After Effects where the background will be added.

My question is: How do I solve this? What format is appropriate? Is there a setting somewhere I have missed to locate?

Thanks for all help!

/Karina