Unwanted woodish appearnce

hello there,
I am working on a doughnut chart
for every piece I draw from THREE.Shape and combine it with THREE.ExtrudeGeometry
dont know how but it looks like this: image

mesh uses MeshLambertMaterial and the top doesnt look smooth it looks like a woodish texture
doesnt look like that when I use MeshBasicMaterial.
is it light direction problem?

That’s hard to tell without seeing your code. How about demonstrating the visual glitch with a live example?

its a little hard for me to write the code to jsfiddle
I am reading the data from a json configuration and using classes.
I will try to implement to jsfiddle as soon as I can