Displacement not working correctly

[gerbilho]

When I apply displacement to the pavement I get this result. See picture.
The map is a grayscale from black to white. Black for 0 displacement, white for 2cm displacement (min level 0, max level 2cm).
Tried to change the displacement screen size to lower values (0,05px) but nothing changes.

Any ideas?

[Ondra]

try pre-tesselating the ground more

[romullus]

Maybe, there's not enough subdivision in your generated geometry. Turn on render stamp and look for polygon count. If it doesn't increase when you lowering screen size value, then it's clear indication that subdivision is too low. Reset screen size to default, set max subdiv per poly higher and then gradually decrease screen size, until you find settings that gives satisfying results.

edit: ninja'd, damn.

[gerbilho]

Increasing the max subdivision by poly to 2000 solved the problem.

Thank you!

[romullus]

Good, but bear in mind that this is global parameter. So, if you have multiple objects with displacement in scene, safer option may be manual subdivision of geometry, as Keymaster suggested or else, situation can easily get out of hand.