I have given a few tries to CrazyBump recently. It is originally made to generate normal maps, but can make very good bump maps usable in Vue as displacements.
I published a tutorial about using Crazybump with Vue a few days ago.

I found that using a diffuse map as bump map, or even pre-made bump maps provided with some textures gives far too many small details and does not look good in Vue, especially with strong bump amplitude. CrazyBump enables me to tune finely the accuracy of my bump map and choose small details or large ones.

The best approach would be to have at least two layers:

• one for the larger details, treated as a displacement map
• another on top of it for smaller ones

Fantasy pictures, free 3d models, 3d tutorials and seamless textures on Virtual Lands.