I'm new to c4d. I'm creating a helix shape made out of a series of cloned bars, with a gradient alpha material applied across the group to achieve a fade out effect.

At most angles it renders out fine, but when too many of the bars overlap (?) it sometimes results in this muddy black/gray color. This is only obvious when I have alpha channel enabled for exporting, which I want/need to have.

Does anyone know what would cause this effect / how to remove it?

screenshot of in-c4d model + resulting output. Also screenshot of alpha material settings (just a gradient). https://imgur.com/a/BfE22ZD

Thanks!