Flickering Particles


I’m using hair particles to generate 70000 fir trees on a landscape. But when rendering an animation, the trees flicker. Possibly because the particles overlap. Or is it a light problem? What’s the solution here?

I already checked if the trees have double vertices (they don’t). And I made sure they render flat (not smooth). By the way, the trees are flat (2D), on-sided meshes.

That’s the scene:

And here’s an anim gif of the problem:


You’re right that the particles are overlapping. This is known as Z-Fighting (when more than one face occupies the same z-space as another). The camera is rendering every other frame choosing between first the one, then the other face in the overlap. Adding some minor rotation to the particles will likely solve the issue; otherwise you might try reducing the density of the particle field.

You can also render with another render engine. Z-fighting is mainly a Blender Internal problem that was never fixed. Try cycles and enjoy the wait.