water - air to underwater transition

[murko-sk]

Hellou,
in mentalRay is possible to achieve soft transition between `air & underwater` like this :

( source http://mentalraytips.blogspot.com/20...rial-arch.html )

How can it be done in Vray ?

[murko-sk]

EDIT : Wrong sample image , i meant transition like this :

[Da_elf]

play with your fog settings would be my guess