Vlado, i beg you!

[Greg3D]

I want a clip map

You can get clip map behaviour using displacement:

It's a snap:

1) Create a plane with texture coords
2) Apply VrayDispalcementMod to the plane
3) Create a B&W or greyscale image (I used a clamped noise for this writeup)
4) Put the B&W image/noise in the Texmap slot of the VRaydisplace mod.
5) Check "Use water level" in the VRayDisplaceMod
6) Change the "Water level" to something other than 0
7) Render

The plane will be clipped based on the water level threshold...think of it as a greyscale threshold.

One thing to note, the water level should be less than the displacement "amount". For my example I used an "amount" of 0.01 (so as to have minimal height displacement), and a water level of 0.001 (to clip closest to black). The greyscale threshold goes from 0 (zero) to the amount of the displacement you set.

Hope this helps.

[Geertvdp]

a clever use of displacement mapping... gotta remember that one...

Nice find Greg !!!

[Da_elf]

but is the displacement method as fast?

[Greg3D]

but is the displacement method as fast?

It certainly is, you're just dealing with simple B&W images here, much like clip maps.

[zerofractal]

but is the displacement method as fast?

whonder how will it behave with million instanced leafs on a an instanced forest. How would it compare to:

- Vray Map w/ mask in the refraction slot and IOR set to 1.0
- Std Material w/ opacity map (the old fashioned way/ which is extremely slow on vray)
- Blend material using the leave as mask
- Vray Displacement w/ Greg's method