I'm creating a 150 frame animation which includes a ground using displacement mapping. Some frames are how I want but many show strange artifacts.

Below are a small segment (frame 4-7) of the animation where the artifacts are worse. Note frame 4 and 7 are unaffected.









I’m rendering in mentalray, FG is off and I’m only using raytracing. The material is a lambert with a displacement map connected. The lighting is 3 point lights.

The problem arises as soon as I add the displacement to the material.


I'm really stumped on this one. Any help will be appreciated!