Test 1:
… other tests soon!
Water feels really like water 
!!!
Curious for the next test!
Water has full geometry, or plane only? that looks absolutely perfect !!!
Water is only plane!
this is superb, but only one sad think is, that VCM is very slow 
But Only VCM can this!
sure, I´m pretty amazed, really, but you cannot use it for exterior render, cos it´ll take ages to get rid of noise
I think for some of the exteriors is possible to use VCM. Exteriors with pools, example.
VFB filters off? I think some filter combination could get rid of noise.
Polymax could you post the scene to learn from it?
please, but this simple 
VCM test.rar (12.9 MB)
VCM is not slow - path tracing would take days to get this quality. There is nothing faster in general for this type of scene
BiDir MLT can do the trick. I was using this method in indigo. It was hella fast for scenes like this comparing to PT BiDir.
Thank you for sharing the file but i have problem i press render in the same setting and i get noise after 2000 pass!
its not like your image , i used A5
Strange! I also use A5 version!
Same here. If I open your scene and click render, the render is very different than your. No caustic.
It looks like some radius is too big.
Polymax, if you render one image with path tracing and one with bidirectional path tracing modes, these could serve as a good reference for people to understand the differences between the algorithms. Path tracing should get both the underwater and the wall caustics noisy and bidirectional should only have problems with the underwater ones.
2 iliyang:
PT + PT can not cope with this task in a reasonable time!
Bidir - give similar results with the VCM, but will not be seen underwater caustics.
The purpose of this test - solve the complex task in the exterior to understand the capabilities of the algorithm. At the moment, none of the popular renderer is not able to!