Vray ambient occlusion and normal rendering (Both should be similar views)are rendered & saved separately. Open both files using photoshop. Now drag and drop the vray AO rendered image over the normally rendered image.
Now you have VRAY AO layer on top of the normally rendered image. Set the blending mode(Layer palette of the VARY AO to OVERLAY, now you can see the both layers blend so well so that you cant see VRAY AO, instead you can see good area shadow. You can control the shadow intensity using opacity of the layer.
Here is a link for VRAY AO rendered image
https://www.facebook.com/photo.php?fbid=103507483097169&set=a.103501516431099.4881.100003137520608&type=3&theater
Have a nice day ahead...
Now you have VRAY AO layer on top of the normally rendered image. Set the blending mode(Layer palette of the VARY AO to OVERLAY, now you can see the both layers blend so well so that you cant see VRAY AO, instead you can see good area shadow. You can control the shadow intensity using opacity of the layer.
Here is a link for VRAY AO rendered image
https://www.facebook.com/photo.php?fbid=103507483097169&set=a.103501516431099.4881.100003137520608&type=3&theater
Have a nice day ahead...