Artifacts in gluCylinder ????

I am drawing some cylinders using gluCylinder and it is showing strange black artifacts on the cylinder if I rotate the scene. Lighting is enabled. does anybody know what could be the problem.

Just a stab in the dark:
Try to enable normalization of normals if you scale the cylinders.

Tried that… didnt work, in the end the problem turned out that i had set the znear factor to 0.01 in gluPerspective. changing it to 0.1 removed the artifact. Thanx anyway.

Another stab in the dark:
Maybe your far limit in the frustum is too big.