In bleakfalls barrow several Draugr can be seen leaving their grave naturally, getting out and standing up then attacking. Not like the reanimate spell that makes them glow and raises them in the air. How can I duplicate that ? I looked at Bleak Falls but do not see how they do it.

I would like to place dead draugr on the ground and then have a trigger revive them so they get up and attack. But naturally not with the reanimate effects and with no black effects on them afterwards.

Any ideas?

It is done through an annoyingly delicate process involving the ambush idle. Check the coffins they come out of, and look at the idle/trigger associated with it.

When you duplicate it, remember to not coc to the cell immediately on game load when testing, or the ambush will malfunction(possibly because scripts are not initialized properly through coc).